MONTHLY WEATHER REVIEW
Editor, W. J. HUMPHREYS
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VOL. 62, No. 8 W. B. No. 1136 AUGUST 1934 CLOSED OCTOBER 3, 1934 ISSUED NOVEMBER 15. 1934
A CLIMATOLOGICAL REVIEW OF THE ALASKA-YUKON PLATEAU
By R. L. FROST
[Weather Bureau office, Fairbanks, Alaska, July 19341
CONTENTS
INTRODUCTORY
Along the western edge of North America the Pacific
Mountain system extends in an unbroken chain from Lower California to Attu Island. This gretit mountain
system includes the Sierra Nevada of California, the
Cascades of Oregon and Washing_ton, and the Coast Range of British Columbia. I n kukon Territory aiicl
Alaska they are known by a number of nariies in different
localities and include the Chugach Range, the Saint Elias Range, the Wrangell Mountains, the Alaska Range, and the Aleutian Range. Here are found tlie loftiest and most
rugged mountains on the continent; Mount McI<inlep, the
highest, being 20,300 feet. The glaciers of this region con- tain a greatei. amount of ice than the total of all others
in the world, outside of Greenland and the Antarctic.
Muir Glacier alone is greater than the 1,100 Swiss glaciers
combined. In the interior, and roughly paralleling the coast, tlie
great Rocky Mountain chain extends the entire length of the continent. In Alaska these are known as the
Endkott Mountains and are said to be the least known of
any in North America. Extensive areas still reniain
unexplored. A bold headland a t Cape Lisburne ~iiarks
the westerninost limit of this great mountain system. Between the Pacific Range and the Rocky Mountain
chain is located a high semiarid plateau, varying greatly
in width and gradually decreasing in altitude from the
highlands of Nevada northward until the coast of Bering Sea is reached. Four river systems provide drainage for
this region. The Colorado in the south, tlie Colunibia and the Frazier near the center, and the Yukon in the far
north. These streanis possess individual features that make them unique. The Colorado is noted for the Grand
Canyon. The Frazier and the Columbia are aiiiong the few rivers of the world that have cut out passages through
a main range of mountains. The Yukon River flows be-
tween the two niountain systenis much as the Colorado
89-1
does a t the southern endof the great inland plateau. IIow- ever, tlie Yukon possesses several characteristics tlint are
esceptiontilly interesting. The source of t l i s great stream is only 25 miles from the coast, yet tlie water must travel
2,300 miles t o reach the sea. The level tundrti land near tlie mouth of the streaiii is so low that the a-ioot tides of
Norton Sound are noticed a t Anclrenfsky 120 miles inland. For about G)i months of the year the river is
frozen over. The spring break-up usually occurs dining:
the second week of May and soon thereufter the river is clear of ice. However, ice in Bering Sea sometimes re-
mains until the latter part of June and Lake LeBarge near
the source of the river is not free of ice until about 3 weeks after the stremi opens. Hence, for a few weeks after tlie spring break-up, the river is open to navigation for 2,000
miles of its course, and get it is closed a t its source and
closed a t its mouth. In the United States and southern Canada the great
plateau region wzis fairly well explored erirly in the nine- teenth century nnct in a comparatively few years becirnie
crossed by railroads and dotted with settlements. How different were conditions in the far north! Alaska was discovered in 1741 and for more than a century the Russians devoted their time and energy to the lucr a t' ive
fur trade of the coastal areas. Long after the first trans- continental railway had ended the covered wagon days
cn the Oregon Trnil and the frontier villages of the west
were developing into important conimercial centers, the great interior region of Alaska remained virtually un-
known. Traders of the Hudson Bay Co. drifted down the Yukon River and in 1847 established a post a t Fort
Yukon. For years t l i s remote outpost of England was the only white settlement in the interior, a region as
large as the State of California. Nearly two centuries have elapsed since white people first canie to Alaska and for 67 years the country has been a possession of the
United States, yet the mass of the public is profoundly ignorant of its climatic features. During the Russian
269
270 MONTHLY WEATHER REVIEW AUQU~T 1934
occupation and for 30 years of American rule almost no
effort was made to record accurate meteorological obser- vations in the interior. The United States Weather Bureau was organized in 1870 a.nd soon thereafter a few
stations were established in Alaska. These were all located along the coast and. records of the interior were dependent on more or less incomplete data gathered by
explorers and survey parties. The most important of
these were: the Western Union Telegraph Expedition of
1865-67, the Coast and Geodetic Survey parties sent out in 1880 and 1891 to determine t,he intersection of the
on0 hundred and forty-first meridian with the Yukon River, and the Geological Survey e-xpeditions of 1898-
1903. Fort Yukon was found to be in Alaska and in 1869
the Hudson Bay post was moved up the Porcupine River
an area of about 24,000 square miles, equal to the State of West Virginia, and resembles very much t,he flat
prairie regions of the Middle Western States. In a milder climate it would be dot,ted with farms and villages
a.nd perhaps supporting a population of 1,000,000. But it is now wholly uninhabited except for a few mining
communities along the northern border. As is true with practically all of interior Alaska the valley is composed of small sluggish streams and marshes and niggerhead
swamps interspersed with thickets of willow, alder and scrub spruce forests. Between the Tanma and the Yukon
Rivers lie the Tanana Hills, a rough region with gentle rolling hills and domes reac.hing a maximum altitude of
5,000 feet. The valleys contain fairly good stands of
timber consisting of spruce, tamarack, birch, and poplar.
into Yukon Territory. The first American settlement in
interior Alaska was Circle City founded in 1893. Gold was discovered in nearby streams and the population of
Circle City soon reached 10,000. The miners proudly acclaimed it the largest log cabin city in the world. The plateau section of Alaska and Yukon Territory
lies principally between 61 and 67 north lat,itude and extends westward to the Kokrine Hills and the Kus-
kokwim Mountains in 155 west longitude. The area included covers about 150,000 square miles and the
present population probably does not exceed 10,000.
Along the southern margin are the loftiest and most rugged mountains to be found in North America, while
to the north are the little known Endicott Mountains. From the Alaska Range on the south to the Tanana
River is located the level Tanana Valley. This valley has
1 As a weather servica under the Signal Corps.
Where trees are absent their place is taken by thickets of willow and alder while almost everywhere may be found
clumps of cranberry and blueberry bushes. As timberline a t this latitude is about 2,500 feet above sea level the
summits of practic,ally all the hills are bare of trees but
are covered with a dense growth of moss and grass and a great abundance of wild flowers. The Yukon Valley lies
just north of the Tanana Hills and is mostly a region of low rolling hills. An exception to this, however, is a region
below Circle known as the Yukon Flats. Here the river spreads out into many channels until its extreme width is about 15 miles. The great stream is ever changing its
course and wearing new channels in the frozen ground until the territory mcluded in The Flats is a maze of
channels, sloughs, and swamps. This enormous swamp
has an area of about 10,000 square miles or approxi-
AU&ST 1934 MONTHLY WEATHER REVIEW 27 1
mately the size of Massachusetts and Rhode Island
combined. From surface to bedrock the soil of practically all in- terior Alaska is perpetually frozen. In prospecting shafts
frozen ground has been reported to a depth of over 300
feet. In this frozen muck are found t,he remains of many prehistoric animals. The bones and tusks.of the mam-
moth are the most numerous. In fact, it seems that few extinct animals have left such abundant traces behind
them. One wonders what killed off these great bet-sts and
how their bones became buried deep in the perpetually frozen muck. Their enormous size niay be judged by a tusk unearthed near Fairbanks in 1932. This specimen
measured 12 feet and 11 inches in length and weighed
295% pounds.
As is true in all regions where mining is the main in-
dustry, the population of the interior country has shifted
about as one field became eshausted and another dis-
covered. Gold was first found on Mastadon Creek in
1893 and an army of prospectors soon gathered in the country around Circle City. At its height Circle is said to have contained 10,000 inhabitants. When the richer
gold fields of t8he Klonclike were discovered in 1896 the
population shifted to Dawson which soon became the
leading metropolis of the interior and contained 30,000
people. The Klondike field reached its peak in 1900
when $22,000,000 in gold was produced. But as the
richer claims were taken up the population shifted to the
Seward Peninsula where gold was discovered on the beach
a t Nome. As activities at Nonie began to decline, a great number of prospe.c.tors explored the interior country and the rich fields north of Fairbanks were discovered in
1902. Gold production increased rapidly until 6he. peak was reached in 1909 when the output for the ye,ar was valued at over $9,500,000. Froin 1902 to 1931 the. Fair-
banks district alone produced $90,830,000 which suni is nearly 10 times the amount paid by the United States for the entire Te,rritory. By 1920 the rich claims were
so exhausted that the expensive hand labor we.s scarcely
profitable and Fairbanks seemed doomed to the inevitable
period of decay so characteristic of mining towns the world over. However dredges were installed and the
gold production has steadily increased until in 1931 t'he output was $2,655,000. Geologic,al surveys indicat'e that
placer- and lode-gold deposits in this region will not become
exhausted for 25 years, so Fairbanks will no doubt con- tinue to be the metropolis of the interior for a quarter of
R century.
METEOROLOGICAL HISTORY
In 1882 the Signal Service of the Army began a system
of nieteorological observations at old Fort Reliance near
Dawson, Yukon Territory, and a t old Fort Adanis near
Tanana. A volunteer observer also began observations a t this h i e a t Fort Egbert (Eagle). Observations were
made by the Coast and Geodetic Survey expedition in
1899 at Camp Coloma on the Porcupine River in latitude
67O25' N., also a t Camp Davidson, Yukon Territory in
1890. Observations began at Circle in 1897 and at Fort
Yukon in 1899. These represent the only records kept in this region prior to 1900 and even these are far from
complete. Some, in fact, estend over a period of but a few months as was the case a t Camp Coloma. The sta-
tions were equipped m most cases with self-registering
maximum and mmimuni thermonieters and rain gages. Three observations were made daily, 7 a. m., 2 p. m., and
9 p. rn. The records kept by the Signal Corps operators a t Eagle, Fort Yukon and Tanana are excellent. The
observers at these lonely, isolated stations have given
faithfully and conscientiously their time and energy to the work. Observations began at the Experiment Station Farm,
4 niiles west of Fairbanks, in Septzmber 1904 and, es- cept,ing for a few months of the early years, the records
are complete. Fairbanks was made a first-order station
in 1929 and the office moved into town with quarters in the Horseshoe Building on First and Cushman Streets.
The thermometer shelter was located on the bank of the Chena River, the elevat.ion of the thermometer being 11
feet above ground. On July 1,1933, the office was moved to the present quarters on the fourth floor of the new
Federal Building. The thermometer shelter was moved to the roof of the building at an elevation of 68 feet. This exposure proved very unsatisfactory. In cold weabher there inv:triably occurs a remarkn ble temperature
inversion aloft. A change in elevation of 100 feet always
shows a ckided rise in temperature. Esperimen ts dur- ing the winter of 1932-33 often showed a difference of
10' to 1 7 O between the temperature on the roof of the Federal Building and that recorded in the thermonicter
shelter on the liver bank. Due to this unsatisfactory exposure the shelter was moved to its former location on
December 1, 1933.
GENERAL CLIMATIC CONDITIONS
The interior country, located as it is between two great mountain systems, has a decidedly continental climate. Exhremes in nearly all climatic elements occur
such as are recorded in Utah, Nevada, and in eastern
Oregon and Washington. The rugged Alaska Range furnishes complete protection from the continuous storms that sweep across the Gulf of Alaska while the Endicott,
Range on the north is effective in turning aside the ste.ady winds that blow in froni the ice floes of the Arctic Ocean.
To the west are the Kokrine Hills and Kuskokwim Mountains, a low detached range extending north and
south across the plateau country. They are usually e.ffective in obstructing the tempering influence of the Bering Sea. Upon rather rare occasions storms move
up the coast of Siberia to a point north of the Aleut,ian
Islands before swinging eastward. These move up the Yukon Valley behind the protecting coast range and produce mild weather with rather heavy snowfall and
furnish some relief from the intense cold of winter. The severe storms that move along t,he Pacific coast each winter have little effect upon t,he interior. A pressure
gradiant of 1.25 inches over the distance of 300 niiles between Fairbanks and Cordova seerns to be necessary
before coast storms are able to pass across the moun-
tains. When this occurs the effect is a slight moderation of temperature, but little or no snow is produced.
The winters are extremely cold and usually very little
snow falls. The wet season comes in June, July, and August and the rain falls mostly as light drizzles. Storms
of the thunderstorm type sometimes move in from the southeast and the rainfall produced may be rather exces-
sive, that is, excessive for this country. The growing season ranges from an annual average of
105 days a t Nenana to 50 days at Allakaket. This may
appear too short for farming but owing to the fact that there is continuous daylight all during the growing season,
this is sufficient for many crops. The precipitation of 7
to 16 inches seems far too light for agricultural purposes. However, half of the annual precipitation falls during the
growing season. In addition to this the perpetually fro-
272 MONTHLY WEATHER REVIEW ATJGUEIT 1934
Zen muck keeps the surface water from draining away and becoming lost. As a result there seldom is any lack of
moisture in the soil. Such vegetables as potatoes, turnips, radishes, lettuce, cabba e, and greens are easily
grown. houses. Beans and peas may be grown during some years.
The season is not favorable for melons, sweet corn, okra, etc. Field crops include hay, barley, oats, and rye. It might be said that truck gardening IS the only practical type of agriculture and even this would not be profitable
were it not for the local markets at the mining camps. As long as interior Alaska is so isolated and remote from any centers of population and competition is so great it is very doubtful if agriculture will ever become a leading industry. For a market the truck farmer must depend
entirely upon the shifting population - of the mining
camps.
Tomatoes and cucum % em are grown in hot-
TEMPERATURE
From the past records a t seven stations the mean an-
nual temperature of the interior country is found to be
32' F. There are few inhabited regions of the world
where such prolonged periods of extreme cold are recorded.
From old settlers one often hears stories of isolated camps whcre the theriiiometer falls below - 80' and remains below -70' for days. However much one may doubt the accuracy of such stahenients, this extreme cold is
not a t all impossible. The records from a network of
cooperative stations at the various rnining camps through- out the country would furnish very interesting statistics
and might reveal some unusually cold locality slmdar to the famous region a t Verkhoyansk, Siberia. Old inhabitants are of the opinion that the settlement of
Birches, below Tanana on the Yukon River, is the coldest place in Alaska. Whether this is due to extremely low
temperatures or to a combination of cold weather and high winds remains to be determined. The lowest
temperature accepted as official for any Alaskan station
is -76' at Tanana in January 1886. While the lowest for the entire region is -80' recorded at old Fort Reliance
near Dawson, Yukon Territory. It is common knowledge the world 0ve.r that tempera-
ture decreases with altitude, but the early settlers in interior Alaska must have been considerably surprised to
find just the opposite condition here. Elevated points
are always decidedly the warmer in winter. Gardens on
the hillsides may have a month longer growing season than
those in the valleys. The aviators were quick to take advantage of this condition and planes often take OR in
temperatures of -50' or lower, then climb to about 4,500
feet where the thermometer may record only 10' or 15'
below zero. No definite information was known regard-
ing this unusual condition until aero-meteorograph flights
were inaugurated as part of the Polar Year program in
1932. The plane regularly ascended to altitudes of 17,000
fe,et or 0ve.r and on freque,nt oc.casions the te,niperature
aloft at no point was as low as that which prevailed on the ground. Slight temperature inversions were first re-
corded in October. As the cold weather of winter became
more severe the temperature inve.rsions became more
pronounced and continued until the latter part of March. Only a t rare intervals were they recorded during the summer months. The most striking example was
recorded on the evening flight of December 28 when the
surface temperature was -41' and a temperature of 1
above zero was recorded a t an elevation of 4,000 feet. At times when surface temperatures were around 40'
below zero it was somewhat amusing to hear the pilot
complain of the heat aloft. The heavy fur parka and
muklulis worn on the ground were uncomfortably warn1
in the higher temperatures aloft. The shutters on the motor cowling were not adjustable from the cockpit and
when the motor was cowled down for cold weather flying
it would at times become overheated in the warm air aloft and prevent the plane from attaining its maximum
altitude. .
Extremely cold weather is practically an annual
occurrence,. Almost every winter the therniomete.r falls to
-60' or lower and occasionally zero or 1owe.r is recorded
every day in a month, and again there are t8inies when the thermoniete,r never rises above zero during an entire
month. At Fairbanks there is an average of 120 days
each year with zero temperatures, and freezing weather
occurs on 234 days in t'he year. The coldest year on record in the mterior was 1909 with a mean annual tem-
perature of 18.7'. The ice in the streams usually freezes
to a thickness of 3 or 4 feet, depending a great deal upon
the amount of snow that falls early in the season. The greatest thickness recorded on the Chena River a t Fair-
banks is 56% inches in hlarcli 1933. In small pools about the gold dredges ice sometimes measures 9 feet or
more. Frosts have been known to ocmr every month of
the year but ordinarily the first frost o fall conies late in
August. At this time there usutdly occur a few freezing nights then follow 2 or 3 weeks of de,lightful Inc1in.n
Summer weather. The mosquitoes are gone, the siinimer rains are, over and the wild berries are to be found every-
where. This period is without doubt t'he pleasantest
time of the entire year. Freezing temperatures and
snow flurries are common after the middle of September. The first zero temperatures occur by the second week
in Octobe,r and the rivers are soon frozen over. With the closing of the streams, winter begins. Temperatures of
-30' are coninion in November, and in December the
thermometer frequently falls to - 50' or lower. January is t,he coldest month with temperatures of -60' or lower
recorded at some point in the interior each winter. In
February the extreme cold begins to mode,rate,, however temperatures of - 50' and -60' are sometimes recorded.
By March the severe cold is over and the thermometer
seldom falls below -40'. Subzero weather occurs early
in Spril but by the latter part of the month the signs of spring me numerous. Freezing temperatures are com-
mon in May but the lengthening hours of sunlight melt
the winter snow and the surface layer of soil begins thaw-
ing. The streams rise and the ice in the rivers breaks up
early in the month. The average date of the opening of
the Yukon River a t Fort Yukon is May 10. On the Titnana River a t Nenana the ave,rage opening date is
May 7 . The Porcupine River does not open until thc last few dn.ys of May. In 1913 Hudson Stuck, leader of the first successful
aswnt of Mount McKinley, left a self-registering ther- mometer at an elevation of 15,000 feet on the mountain.
Nineteen years later the the.rmonieter was found. The
niinimuni temperature reading will never he known as
the thermometer was graduate.d to -95' and the indi-
cator in the tube had be.en forced back into the bulb, apparently indicating a temperature of more than looo below zero. Howeve,r, a tempe,rature even of -95' is lower than any natural temperature ever before recorded
on the earth's surface. There seems to be some doubt among certain authorities as to whether or not the
thermometer was exposed properly. One member of the expedition was interviewed a t the Fairbanks office and both still and motion pictures were e-xhbited of the
thermometer when it was found. There seems no
reason to doubt the accuracy of the incident. It was
:hly Weather Review. August 1934
Rimr ~i i i a .
An~nsT 1934 h4ONTHLY WEATHER REVIEW 273
stated that the thermometer was resting in a slightly
inclined position with the bulb end uppermost. By using the temperature of -95 and the maximum
temperature of 100 recorded a t Fort Yukon we have
an absolute range of 195 for interior Alaska. However, the unusually low temperature occurred high on the
slopes of the mountain and entirely out of the inhabited
portion of the country. The absolute range for the inhabited region is 180 and the absolute range for m y
one station is 178 at Fort Yul~on. Rapid changes in temperature soriietitiies occur, one
of t8he most remarkable of which was rcc,orded at Fair-
btt1dis in January 1934. On the 6th the maximum tem-
perature was 34 and on the 14th it had dropped to a inininiuni of -66, making a range of 100 in S days.
Later in the month a change of 72 was recorded in
2 days. To the people of the far North the extremely
low temperatures are not as objectionable as might be
imagined. To the residents of Dixieland a plain acc.ount of the cold no doubt may sound dreadful. The differ- ence lies in the ma.nner in which one is prepared for winte.r weathe.r. With wmii clothing and well-insulated
houses a temperature of -40 produces scarcely any
inconvenienc,e whatever. The fact that the thermometer
falls to 60 below, or lower, means very little to the
daily life of the people. The extreme cold causes no
more inconvenience than ze.ro tempe.ratures in the South. The rne,re cold alone can easily be endured, but when
it is combined with even the slightest breeze it becomes
almost unendurable. Another disagreeable feature al- ways assoc.iated with estreme cold is the winter fog.
At Fairbanks de.nse fog always ac.companies tempera-
tures of -45 or lowe,r. The, records for January 1934
show 348 hours with temperature -45 or lower and
during t8his t8iriie, the.re we,re 320 hours of dense fog. On one, oc.casion the dense fog prevailed for 155 conse,cxitive
hours. During t,he coldest period the,re were tlire,e
successive da,gs with mean temperature -60. It is
very interesting to observe the formations of hoarfrost
in cold weat,her. At -50 brick and stone chimneys leading from he.ated st0ve.s always develop c.rowns of
hoarfrost 6 or 8 inche.s high which rese,nible very n1uc.h
the formations around geysers and hot springs. A
similar c.rown of frost forms on the ventilator outlets of
heated budclings. The telephone wires, trees, fences, and
all esposed objects become festooned with hoarfrost and produce very picturesque landsc,apes. Mounds of frost
are built up around the base of all shrubs and small trees and if the extreme cold continues for a few weeks
the plants may become entirely covered. A weird sight
it is to look out across the level snow-covered country
and see thousands of these frost mounds 2 feet or more
in he.ight dott8ing the landscape. Truly interior Alaska
in midwinte,r is a photographers paradise.
Alhhougli the winte,rs are very cold, the summers are at times uncomfort,ably hot. Accounts of the early es-
plorers on the Yukon River no doubt greatly astonished
bheir readers. Lieutenant Schwatka, leader of an espe-
dition in 1878, wrote as follows:
The 29th of July was a hot, sweltering day with the sun and its thousand reflections sending their blistering heat into our faces. In fact, our greatest inconvenience, near the short Arctic strip of
the stream, was the tropical heat * * *. We drifted down the hot river by low bauks that needed nothing but a few hreech-
clouted uegroes to convince us that we were on the Congo.
Dr. W. H. Dall, leader of another expedition, wrote in
1 sso:
A t Fort Yukon I have seen the thermometer a t noon, not in the
direct rays of the sun, stand at 1 1 2 O , and I wa4 informed by the
commander of the post that several spirit thermometers, graduated up to 120, had burst under the scorching sun of the Arctic mid- summer.
And again:
In midsummer on the upper Yukon the only relief from the in- tense heat, under which the vegetation attains an almost tropical
luxuriance, is the brief space during which the sun hovers over the northern horizon, and the voyageur in his canoe blesser: the tran- sient coolness of the midnight air.
I t is very improbable, though not impossible, that a tem- perature of 112 was ever recorded by a properly esposed
thernioinet8er anywhere in Alaska. Most certainly 110
properly esposecl t8herniometer has ever gone to 120.
I t is not at all uncommon to see thermometers in the sun
standing at 110 or over. The highest temperature re- corded by a properly exposed thermometer is 100 at
Fort Yukon. The maxima at other stations are: Fair- banks, 99; Tanana, 91; Rampart, 97; Circle, 96;
Eagle 93. Anyone who spends a summer in interior
Alaska or Yukon Territory will most certainly be con- vinced that some days are unbearably hot and sultry.
As a rule the long days of sunimer are cloudy and cool,
but brief hot spells do occur in late June, July, and early
August. Days with masimum temperature of 80 or over are very sultry and oppressing, producing a feeling
of discomfort equal to a temperature of 100 in the mid- western States. In addition to the discomfort caused by 
the heat, one must endure the hoards of vicious mosqui-
toes and the troublesonie gnats. Some idea of the Arctic mosquitoes may be gained from the following account of C. F. Hall:
Among the numerous visitors that greeted us on our arrival, I was astonished to find myriads of miisquitoes. Little did we expect so warm a reception in the Arctic regions. Talk about musquitoes
in the States as being numerous and troublesome! Why, no man who has not visited the Arctic shores in the months of July and August can have a good idea of these liiiputian elephants.
In the States the very hum of a musquito is enough to set any one upon his guard. How many a poor soul there has been kept in a state of torment all night by the presence of only two or
three musquitoes! But here, in the North, it is a common, every- hour affair to have thousands at one time around you, some buzz- ing, some drawing the very life blood from face, hands, arms, and legs, until one is driven to a state approaching madness. Even the clothing worn in the  States  is no protection here against the huge probosis with which each lady musquito is armed.
It can truthfully be stated that the mosquitoes are just
as numerous now as they were 74 years ago when Hall
first journeyed to the Arctic regions.
The account of Dr. Dall is somewhat8 niisleacling.
COLD WAVES
The term cold wave as applied to regions in the
States has little meaning in the interior of Alaska
unless one thinks of a c,old wave as lasting 2 or 3 months.
There are times when minimum temperatures of zero or
lower are recorded each day for a period of 1 or 2 months.
There are occasions when the maximum temperd.ture
re,niains below zero for an e,ntire month. In the Northern
State,s a cold wave means a drop in temperature of 20
in a 24-hour period, to a minimum of zero or 1owe.r be- tween December 1 and March 15, and to a minimum of
16 between March 16 and November 30. Cold waves
are not as frequent in this country as might be supposed, for when winher begins the temperature falls and remiins
fairly constant over long periods of time. a t times,
however, high-pressure areas move in from Siberia and
send the temperature from its shady low point down
to a figure, far below the limit of mercmial thermometers.
The first cold wave ip the fall is important, as it inarks
274 MONTHLY WEATHER REVIEW AUGUST 1934
First Byrd Antarctic Expe- dition- - _____.___..._._..
Amundsen dntarctic Er- pedition ._.. .. ..____ __ - _.
Belgica Antarctic Expedi- tion ___....._____._______
Cape Adare Antarcti ca.... McMurdo Sound Antarc- t,iw ......__.._____...__-.
2nd Grinnell Expedition, latitude 78'37'N ..____ ..-
Peary Expedition to North Pole .__...._... __._._____
Verkhoyansk, Siberia-----
tlie e.nding of the season's work on the gold dredges. As r:iining is the main industry, most activity ceases and the
lthorers spend the wint8er in town or go "outside". It is interesting to follow these cold waves southeast across
C!anada and on until the Atlantic States are. reac,he,cl
iibout 2 wee,ks later. The c.old wave that set a new record
of -66' a t Fairbnnlis in January 1934 was fe,lt in hlnssa-
chiisctts 15 clays late,r. Aft8er be.ing in operation more
t1in.n 30 years t8he station a t Fort Yukon was closed aatl
official records ended on January 12, 1934, with a mini-
i11uni teniperature for the day of -64'. Had the, station
been in operation 2 days later, a new low temprature re,corcl would have been established for Alaska. At 9
a,. 111. on t>he 14th the t8emperature given in ;1.n &rwaps
report w8.s -75', and later in the day the thermomete,r
was observed at -78'. This is 3' lower than the officid record established a t Tanana in 1886. In February 1932
a privately owned thermometer at Alatna, near Alla.kalie,t,
registered -82O, but this thermometer was destroyed
by fire before it c,ould be secured for testing at low te,mpera.ture,s. During 19 years of conc,urrent rec.ords at
Allakaket and Tanana the. minimum tempe,ratures for
January and February were invariably lower at Allaliaket, the average being 9.4' for January and 11.7' for Febru-
ary. During this period --TO', Ilie lowest, was registered three times at Allakaket; the corresponding minima at
Tanana were -68', -62', and -68'. There can be
little doubt that temperatures lower than -76' have occ,urred a t both Fort Yukon and Allakaket since the
record was established a t Tanana. The most severe
cold period on record at Fairbanks was that of January
1934, whm the temperature ave.raged -51.0' for 3
weeks. The minimum was -66' and the,re were 2 days
when the inaximuni w a s - 56O. However, t8his cold
period fdls far short of tlie one that occurred in Decem-
ber 1917 a t Dawson, whe,n the temperature ave,raged
-51.3' for the month. To better comprehe,nd this es-
treme cold one has but to c.onipare it with othe,r re,gions of t8he world. The lowest temperature encountered by
Peary on his dash to the North Pole was -53O. As yet the, lowe,st temperature rec.0rde.d in the Antarctic is
--73.3', reported by Ainundsen at Framhe,im in 1911.
Some members of the Scott Espedition were, said to have encountered a tempe,ratiire of -77' near Cape Crozier
in 1911.
The following table is a record of the minimum tem- perature and the lowest monthly mean recorded by vari-
ous polar expeditions as well n.s for a few inhabited
re,gions of the world that are noted for extremely cold winters. It is interesting t'o conipare these with similar
records for the Alaska-Yukon country.
OF. -72
-73
-46 -43
-60
-69
-53
7 9 2
O F .
-44.7
-48.1
-10.3 -13.4
-21.5
-38.1
-31.7 -59.0
Tibet ___._____._____ ._.____
Leh, Kashmir (11,500 feet). Mist!, Andes Plateau altitude 19 200 feet....:. Mount W)asi&gton, N.H., 1933---.-.-....--.-.-.-..
Fort Reliance(Dawson)- -.
Fort Yukon _________.__...
Tanana. _______ __ ____......
Eagle ......___ ________...__
Allakaket- -. . .. - - - - - - ._ ._.
Fairbanks.. . . . . . . - -. - - -. _.
Mount McKinley _._______
OF. - 40
- 19
-46 -YO
- 76 - 76 -75 -70
- 66
3-100
O F .
19.0
1 17.3
121.4
5.0 -51.3 -48.4 -36.7 -45.8 -44.8 -36.6
I Lowest mouthly normal.
2 The lowest monthly mean -49 4' at Fort Yukon is much too high RS -39' XRS o w l
a i the ma~imum temperature on 26 days when mercury was frozen. This occurred iu 1 )rwniher 191 7 - . . . . -. . -. . .
J Al~solute minimum unknown,
PRECIPITATION
Located within an area protected by niountains the interior country is semiarid. However, the terni semi-
arid is somewhat misleading. For 6 months of the year
tlie grouncl lies frozen beneath a niantle of snow. In summer tlie deep lnyer of iiioss and decayed vegetable
r acts ns a niulcli wliicli effectively holds the
moisture in the %foot layer of thawed ground. The precipitation is light. I n the northern section Fort
Tulion hns an nnnual average of only 7.28 inches. To the westwircl the precipitation steadily increases as tlie dis-
tance to the Bering Ses decreases. With the exception of
tlie slopes of the dlaska Range the grelitest precipitation
is recortled a t Hot Springs, the nnnual average there being 16.15 inches. The variation in the greatest pre-
cipitation recorded in 34 hours is considerable, ran ing
from 4.0 inches a t Tunana down t o 0.07 inch a t old 8ort Reliance. This shows that the niaximuiii rainfall in a
clay, like the mean annual precipitation, is greatest in the
western section nearest the Bering coast. The period of
heaviest rainfall occurs in June, July, and August, while the least is recorded in February, March, and April. At
Fairbanks there is an average of 92 days annually with
0.01 or more precipitation. As is indicated, the rains
are light, rarely measuring as much as 0.25 inch in a day.
Due to the thick covering of moss over the frozen ground the soil is cool and damp. Evaporation takes place slow17
and the humidity of the air is greater than in most semi-
arid regions. The water vapor is carried aloft and upon
cooling is formed into cumulus clouds that produce occa- sional thunderstorms. At times there are heavy shon era
of short duration followed by clearing skies, but most of
the rain falls as steady light drizzles that i n a y continue
for several days. The greatest precipitation for any one month on record is 8.19 inches, in August 1930, a t the
esperiment station near Fairbanks. At rare intervals the thunderstorms are acconipanied by hail. The hnil-
stones are about the size of buckshot; and as the stornis
last but a few minutes, there is little or no damage done.
An exception, however, occurred a t Allnkaket in July 1921
when a hailstorm was severe enough to daniage the
garden crops. At Fairbanks hail has been recorded but
10 times during the past 5 years.
SNOWFALL
Upon rare occasions the first snow of Autumn may fall
in August and by the middle of September snow flurrie.s are quite common. Howeve,r, it is not until the middle
of 0c.toher that any appreciable amount of snow falls and remains on the ground. The heaviest snows occur in
January, while October and March rec.eive the least
during the cold winter. Even during the midsummer
month of July snow is sometimes reported a t JVGsenian. From the latter part of October to the niiddle of March
the.re are very few occasions when the temperature rises
above 32', and as a result the snow accumulates on the
grouncl to n depth of 3 feet or more. This often gives
:in e.rrone.ous impression regarding the total snowfall for
the wason. The ave.rage snowfall in the interior IS about
50 inches. Very little diffe.renc,e c.an be noted between
the different sections on the Yukon nnd Tanana Rivers,
as hot8h tlie grea.test and the least mean annual amounts
we.re re,corile.d in the eastern section. The greatest annual snowfall of whkh records are. available is 110
i n c h at Allitkaket in 1921, while the least is 13.9 inches
at Rnmpnrt. The, snow is selcloni dwp enough to inter-
fere wibh traffic snd t,lie,re. RI'C t,inie.s when it is so light as
Anans~ 1934
January _________________ 81
February_--------_------ 76 March____--__----------- 66 April .................... 61
M a y __________________-_- 58 June ____________________ 62
MONTHLY WEATHER REVIEW
J d y _______________-_-___ 66 August_----------------- 74 September_____---------- 73 October -_______..__---___ 72 November______--------_ 81 December ______-_--.._-___ 83
275
to impede sled travel. Due to the extreme cold, the snow is light and dry. Only rarely does it fall in hrge feathery flakes so conimonly seen in temperate regions.
Over most of the country the wind in winter is light and
variable, with long periods of calm. As a result the snow
remains fairly evenly distributed over the ground. At Fairbanks there is an average of 184 days each year with
1 inch or more of snow on the ground. The snowfall of the winter of 1928-29 is no doubt the most notable of
recent years. At Fairbanks the total snow for the season
amounted to 94.7 inches. There was little or no property
loss, but c,onsiderable inconvenience was esperiewed in
keeping the streets cleared and in obtaining fuel. The he.aviest 24-hour snowfall on record at Fairbanks is
13.0 inche.s. One peculiarity of the dimate is the ex-
terided periods of light snowfall. There are occasions when the fine, dry snow falls continuously for several
days yet the accumulated depth may amount to scarcely
more than a trace. At times the snowflakes are so small as to be practically invisible unless observed against
a dark background. In regions outside of Alaska one sometimes hears the espression, "It is too cold to snow. "
It would be of intemst to know the lowest tempera-
ture at whic,h snow has ever been reported. In interior
Alaska snow often occurs a t temperatures far below
zero. During a mild storm on January 16, 1934, Jarvis reported snow a t -38', McCarty a t -40, Richardson
a t -49', and a t Circ,le, heavy mistlike snow was re- ported at a temperature of -52'. Due to the almost
total la& of wind during the cold weather, blizzards are
virtually unknown over most of the interior country.
FLOODS
Floods occur almost annually on the larger streams
and a t intervals of several years they assume destructive proportions. The floods are local and are caused by ice
jams following the spring breakup. A mild winter with
heavy snow is sometimes followed by a cold spring, and water in the rivers remains low and frozen tight. Then
with an abrupt change the days become warm and the streams rise, causing the ice to break up quickly. When
this occurs the ice is piled up in tremendous jams a t the narrow points of the streams and floods follow. In 1930
the Chena River at Fairbanks rose 12% feet above the normal water level. Practically the entire town was
flooded and it is said that water was 2 feet deep in the business district. Considerable property loss occurred.
The Yukon River is Jometimes dammed by immense ice
jams near Fort Yukon, and when this occurs the strea.m rises and spreads out over the Yukon Flats until i t is 15
to 20 miles wide. At Circle, City the stream has bee,n
known to rise 25 or 30 feet and flood the entire city until water stood 6 feet de,ep in the post office. Summer floods
sometimes occur on the Tanana River and other streams
originating. in the Alaska Range. These floods are caused by the rapid melting of the glaciers during the unusually hot weather. Owing to the sparsity of population, about
one person for each 15 square miles of land, the damage due to floods IS comparatively light. With but one high-
way and one railway in the country there are but few bridges to be washed out, almost no livestock t'o be drowned, and few indeed are the towns to be destroyed.
-
CLOUDS
Almost without exception the semiarid plateau regions of any country are noted for their c.loutlless skies. How
different is the interior section of Alaska, for here pro- longed cloudiness is the rule. At Fairbanks there is an
average of 88 c,lear, 89 partly cloudy, ancl 188 cloudy
days each year. The mean claily cloudiness as deter-
mined from 4 years of records is 6.4. The periocl of greatest cloucliness falls during the summer months, the
mean for August being 8.0. During tlie brief intervals of daylight in winter the sky is usually obscured by ground fog or stratus clouds. As the seasou. of extreme cold ends,
the cloudiness decreases and clear skies generally pre- vail from the lat,ter part of February t>o early in April.
Then when the warm days of spring appronc,li there is a
decided increase in claily cloudiness. During tlie continu- ous daylight of summer dear days are the exception, but
as summer ends and the cool days of the short autumn
season begin the cloudiness decreases. The period of clear skies in autumn is very brief, for as cold weather
begins, in October n.nd November, the cloudiness increases
and continues until the cold cla.ys of winter are over. Stratus and alto-stratus clouds predominate in ?inter.
Cirro-stratus clouds are commonly seen and occasionally alto-cumulus are recorded. Strato-cumulus begin to
appear in March. About the second week in April the cumulus cloucls are first seen. As they are the first signs of spring, they are a welcome sight and are a relief
from the dull stratus clouds t,hat prevail during the long
cold winter. During the warm summer days moisture evaporating from the wet spongy moss rises and forms picturesque cumulus clouds, the beauty and grandeur of
which are almost without equal in other lands. One charac,teristic of the inland country is the rainless thun-
derstorms. On almost any clear, calm morning in July a few small cumulus clouds may be seen on tne south-
eastern horizon. These increase and by midafternoon the sky is filled with turbulent thunderheads which roll
and tumble about above. They are very dark and threatening and a downpour seems imminent. Perhaps
a little rain will fall, but usually as evening approac.hes
the clouds begin dissipat'ing. The phenomenon has all
the characteristics of a typical thunderstorm, but there is seldom any thunder to be heard. At Fairbanks thunder
is recorded on an average of seven times annually. The
sound is usually weak and far distant. The terrific
crashes so common in the thunderstorms of the Midwest are seldom ii ever heard in interior Alaska. True cirrus
ancl cirro cumulus clouds are some,times observed in the
spring and fall, but only at rare intervals.
276 MONTHLY WEATHER REVIEW AUQUBT 1934
Percent
January ________________ 29 February- _____ - ________ 51 March ______________-___ 70 April ___________________ 67 May __________________- 52 June ___________________ 61
Prrrenl
August _________________ 32 September- _____________ 28 October ________________ 33 November ______________ 33 December __-____-_______ 38
Annual mean _-______rr-- 45.3
Solar-radiation records have been kept at Fairbanks
for t)he past 3 years. Due to t,he high latitude of the stat,ion, t)he continuous rec.orcls are of great interest. During the c,loudy weather of December t8here have been
clays whe,n no radiat.ion whatever was received during
t.he 3.7 hours the sun was above the horizon. The mean daily amoun t of radiation in gr-cnl. per square centmimeter for December is only 5.3. In June, with a niasiriiiun of
31.9 hours of snnlight, t,he metin is 476.7. The greatest
ainouiit received in any one day was 714.2 on June 22,
1933.
WINDS
F d j d i s is the only station at which complete wind
records are, kept,, but it is believed t,hat conditions are very much the same over most of the interior country.
Perhaps t,he most striking peculiarity of the cliniat,e is
the total lack of wind for long periods during the winter
months. January, the month with the least wind move- ment,, has an average of 333 hours of calm. The greatest
nunibe,r of consecutive hours of c,alm is 51, in 1934. I n January 1934 there occurred a period of 52 hours during
w1iic.h but 1 mile of wind was recorde,d. The hours of calm in January 1933 numbe,red 399, whic,li is 54 percent of
the t,otal liours in the month. The highest wind niove- ment occurs in May, wlie,n the mean monthly velocity is
5.7 rides per hour. The highest velocity ever recorded at Fairbanks since the automatic recorder was installed
was 32 miles pe,r hour on Mag 12, 1934. So accustomed
have the inhabitants becoiiie to the quiet air that veloci- ties of IS miles per hour or over are very disagreeable. There is an average of 11 days each year with masiniuni
ve.locities of 30 mile,s pe,r hour or over, but even t>hese modernt~e winds are of short durat,ion. The 3 gears of
rec,ords at Fairbanks show a t,otal of 4 days when no
wind movement was recorded. Only three t'imes has the, d d y tot8al movement exceeded 300 miles, the highe.st
on rec.ord being 367 miles. The total monthly movement ranges from a minimum of 1,020 rides in De,cember 1931
t'o a maximuin of 5,311 in h4ay 1934. During the winter the light winds are quit,e variable, there being tinies when
scarc.ely 2 consecutive hours during a clay have the same direction rworded. However the prevailing direc-
tion in winter is from the northwest and in summer from
t,he southwest. The highest velocities are usually from
the northe,ast. The section of c,ountry near the confluence of the
Tanana and Yukon Rivers is quite exceptional. I n this region the river valleys furnish a drainage system for the air from the interior plateau. gbout 75 miles above
Tanana the Yukon River enters a narrow gorgelike valley t#hrougli which it flows in a series of deep rapids.
In winter a high-pressure are8 usually prevails over
interior Alaska while to the. southwest is the rather per- ma.nent Aleutian low. This pressure distribution is favorable for easterly winds over the interior. I n most
sections these winds are not enc.ountered to any ext,e.nt
on the surface but down the two river valleys, from Rampart and Hot Springs westwa,rd, the easterly gales rage at subzero temperatures frequently throughout the winter. In summer the general pressure distribution is
reversed and the weste,rly winds prevail. No wind records are made in this re.gion but the temperature rec.ords show a niininiuni of -76' at Tanana and -6S0 at Rampart. Ot8her regions of high winds are reported
in t,he vicinity of Bet,tles, where the Koyukuk River flows clown from the Endicott hIountains, and on the Chandalar River which flows down from t,he mountains fwther to the eastsward. Stories are told of high winds
encountered on the sled trails with the therniometer
AUQUBT 1934 MONTHLY WEATHER REVIEW 277
standing a t 58' below zero. Truly these regions must
closely rival "The Home of the Blizzard" whic,h the Mawson Espedition encountered in the Antarctic. The
gales sweep the snow from the rivers and leave t'be ice polished and smooth as glass. Travel by dogsled is very difficult, for at tinies the dogs, sled, and driver are blown across the smooth ice and piled up in the brush along
the shore. High winds are also oft'en encount'ered at
high elevations such as E q l e Summit,, the divide be,t,ween
the Trtnana and Yukon watersheds on t,he trail from Fairbanks to Circle City. With these esc,eptions the
interior of Alaska is noted as a region of very light wincls.
The mean annual velocity at Fairbanks is 3.8 miles per
hour.
PILOT-BALLOON OBSERVATIONS
Pilot-balloon observations begsn a t Fairbanks, August
26, 1930. Due to the unusually clear sir and relatively
light, winds aloft, the balloons are sometimes followed t'o
very high altitudes. On March 14, 1931, an observation lilsted 122 minutes and if the ascension rat'e remained
constant the balloon was lost a t an altitude of 72,600
feet. The records for this unusual observation appear very good for 108 iiiinutes but beyond that point they
may be somewhat questionable. The alt,itude a t 108
minutes was 19,530 meters and the horizontal dist,ance
44,800 meters. On May 23, 1933, a balloon was aban- doned a t a distance of 60,600 meters after being followed
for 100 minutes. This is the greatest distance to which a balloon has been followed. The varying c,ondit8ions
under which these observations are macle adds int'erest and variety to the work. In winter the prevailing ground
fogs hinder the \+Torli a great deal, but observat,ions a.re
frequently made at t8enipernt,ures below - 40". Tlie
coltlest run was made a t 53' below zero. Tlie wintls
aloft, are usudly moclerat'e t'o fresh a,nd only rarely are
velocities of 40 miles per lioiir or over recorde,cl. It, is interestsing to not8e t'lie winds aloft that somet,inies prev-nil
during periods of high :i,nd low baroniet,ric pressure. During an observat,ion on Ochober 13,1933, t,he bnroiiieter
stood a t 29.02 (reduced to sea level) and t81ie highest
velocity recorded was 4 miles per hour. The balloon entered alto-stratus c.louds a t 9,200 feet, being only
1,100 feet away horizontally. Eight days later t,he
barometer stood at 30.93 and the balloon observation
revealed winds of hurricane force aloft. The velocity
a t an elevation of 24,000 feet was 78 niiles per hour.
RADIO METEOROGRAPH OBSERVATIONS
An interesting part of the Second International Polar
Year program was the radio-sounding-balloon work.
Regular sounding-balloons were released cariying aloft small radio transmitters which autoniat,ically sent out
teinperature and pressure data. The signals were picked
up on a short wave receiver in the office. The balloons were also observed through the theodolihe and t,he winds
aloft plotted in the usual manner. The balloons were
given an ascension rat'e of 200 meters per minute ancl un- der favorable conditions complete records were obt,ained
until the balloons burst. The rnasimum dtitucle rca.ched
was 18,355 met8ers and the greatest clistmce to w1iic.h the
brtlloons were follou-ecl wa,s 62,700 meters. One brilloon was followed to n distance of 83,500 ii>.eters, but t8he records for the last few niinut,es of the observat,ioii are
soniewhat questionable. It is rather surprising t>o note
t'hat in prac,t'ic,ally ei7ery instance t8he long pilot- ant1
sounding-balloon observntions revenled east,erly u-inds
high up in the Stratosphere. Duiing the spring :mcl
summer that radio sounding-balloon observations were
made, t,he niem altitude of the stratosphere was found
to be 11,800 meters.
CHINOOKS
A fmv occasions occur each year when the pressure gratlieiit Mween tlie interior and tdie coilsh becomes so
great t8hat n-rild st80rnis pn.ss over the niount a.ins m d ca.use
:L cliii~.ook c.onclit,ion to prevail. During t,liese pe,riods, winds of strong t'o gale force prevail tiloft and a few
foelin cloucls ma.y he observed. Alt81iougli tfemperrrturcs may rise 2O0 or more, tlie t~liawing usually associated wit,li chinook winds docs not' occur, for soltlom does the
t81ieriiiometer rise above t8he freezing point diiriiig winter.
In January 1934, n, storm moved in across the mountains and result8ed in what niight be t,eriiied " cliinook condi-
t.ions." The t,enipcrature at, Fairbanks rose rapidly to
- 35O, but when t'he storin moved away t'he temperat,iire
dropped to -60' for the second t'iine duiing the month. The warm chinook winds of t'he Midwest'ern St'ates are
almost unknown in the plateau section of Alaska.
BAROI\IETR.IC CHANGES
A soniewhat surprising cliarecteristic of the c1iniat)e is
t'he litt81e effect produced by est,remes of barometric pres- sure. The violent storms usunlly associa.tec1 with unusu-
ally low baromet'er readings m e unknown. In fact',
interior Alnska is a region where violent storms are
virtually unknown. Periods of low pressure are often accompa.nied by mild weather wit'li lit,t,le or 110 wind,
while the opposit'e effect is soimtimes not.iced during
periods of iiziusu:i.lly high pressure. Durii!.g the pnst 3
years t,lie bnromet,ric pres5ure nt, F:iirbn.nks lias been
below 29.00 inches on seve,n occ:i.sions, the lowest, being
2S.73 inchs. Two times in 1933 tbe prcssure W R S ahovc
31.00 inc.lies. On RI:rrch 1, 1934, il prcssiire of 38.73
inches (sm level) ~m s recorded. On the Gt,h tlre bn.roin- eter liad risen to 30.76 inches, ma.king a range of 3.03
inches in 5 clays.
HALOS
During the cold days of winter the sun shining throilgh
cirro-stratus cloucls often produces very int,erest,ing
halos. The ordinary halo of 22' is frequent,ly observed. The great halo of 46' is noted seve,ral times each year
and upon rare occ,asions t,hcre occurs a conibination of
halos, arcs, and pn.rhelia that is t)ruly marvelous. Such
a display occurred on April 7, 1933. On t,his occasion there was a very brilliant circumzenitha.1 arc, a great
halo of 46', a parhelic circle, two parhelia of 2 2 O , and a
paranthelin of 120'. The displtiy w-as re,peate,d on the following day, n.lt.liongh not on so grand a sca.le. This display included the brilliant circumzenit,hal arc tangent to great, halo of 46'. The parhelic circle a.nd paranthelia
of 120' were not observed, but a halo of 22' wit,li n tangent
arc on t'he upper surface wa.s present, inside the great
hn.10 of 46', as well as two brilliant, parhelia of 22'. On June 23, 1934, a very peculiar halo was observed. The upper and lower surface,s were 22.2' from the sun, while the right and left surfn.ces &-ere. a t n distance of 32.7'.
In additsion, t8here appeared a quart,er arc on t8he lower riglit.-hand surface at a clist'ance of 39.7'. Then upon t,he lower surface was a t,angent arc pn.ralle1 t,o the horizon.
Parhelia are observed more frequently even t,lian t'he halo
of 22', nnd at t,inies they are exceedingly bright,. On Jan-
uary 16, 1934, right a.nd left parhelia. were observed, t,o- getlier 1vit.h a light pillar and the rare vertical parhelia.
All were exeedingly brilliant ancl remained visible for
278 MONTHLY WEATHER REVIEW AUQU~T 1934
STATION
EaFrhanka ..........................
Uemm ....
nbout an hour. On several occasions paraselenae have
been observed, and on clear, cold nights a full moon shining through n few thin alto-cumulus clouds sometimes produces coronns thnt are wonderful to observe. I n this connection might be mentioned the colored nlto-
cumulus nnd alto-stratus clouds that are sometimes
observed when no parlielin or halo is present. Usually these nre small detnched clouds nbout 15 to 20 from the sun. They niny include nll the colors of the rainbow
and resemble delicate mother-of-penrl.
REMARKS-
FIELD CONDITION
CEILING VlSlBlUTY WIND DEW OAROM-
TVRE POINT ETER
ELEVA- TIME
GENERAL CONDITION TlON
(FEETI P. M.l (FEET) (MILES1 AND vELoclTY (DE=. F.1 (Om. F.1 (IULNN
(A. M. OR
-- -___ ~--
-8s ....... ...a snae. ..fog ... .z.erD .... .z e .r ~ ....... calm ....... ..-e ................. 8L4I). ....................................
..nlr .............................. ._ ......... .m.l_.____ .ml- ........ calm ....... .--& ................ ?10...3!3. .gmb.f ~g..a.. ........ ............
AURORAS
As might, be expected in this lntitude, a.urora1 displnys
are frequent. There is an a,vera.ge of 176 da.ys annually
on which they a.re recorded. There seems to be a popular belief tha.t t,he a.urora is genernlly nssocinted with cold
weather. Records nt Fnirbanks show little connection
Ha t... SprAnge.. .................... .ZZO..a.. .-clr- ......................................... .ml...... .w.l_____. ... calm ....... --r70--*-
~anana ............................... .ut1 ...... .unl...... ... calm ....... -4 2
iul&rrrth ................... . la.. ...... .chi.... ..... ................... .unl______ .unl.... ....... 8 ... l....... Ai&
Ridardaoa. ....................... .Z.&S.. ... clr..l..fQg ............ ........ .urd ...... .pmr ....... c.ah ....... ..d4
Mkar-tp ..........
___I____
.. -246~~. .. denae ...fig ______.______-_ .Zaro .zeXD .-.9...4... ..-6.1_____
J a r .a ~ .. .z.era... .zmm... ...C.&!!....... ..:M
Circle __.___________._ ................. -23Qa. .--ab..- .unl...._. .unl______ ... WU. ....... ..-IIC!
+Eart..mkan ........................ .?%&a. ~1.r.- ........................................ .unl_____ .unl____ ..... c a l m ....... .-Yh
. .243a.. .-.ah
......... .... ....... .....
. ______._ .. ........_ .?!&a- ...a anm ... fQg
........
........................... ... ............ ... .......
disturbance seems to be to the southwest, near the Val-
ley of Ten Thousand Smokes. Many nctive volcanoes are located in this region. The eruption of Mount Iiatmni in 1912 wns one of the most terrible known sny-
where on the earth.
AVIATION
Commercinl aviation is playing such a great pnrt in tlie development of interior Alaska t,lint this article would
hardly be coiiiplete without a few reninrks regarding this
modern menns of transportation. For nbout 15 years following tlie discovery of gold, the shnllow-clrnft river
boats furnished the only menns of summer transportation. In winter d l traveling was by dog sled and this condition
still prevails over much of the country. In 1905 tmhe
Alaska Road Coniiiiission wts organized and a road was
constructed from Vnldez, on the coast, to Circle City on
the Yukon River, a distance of 500 miles. In addition
8Q..S2. .pst.cha.8rn&fag
................. 29.,95 ....................................
................. Ua.9Q ..ptchas.gm&fag
.................................................................
............. ................................. ____-_
........................ ....................................
............... ..29,62 ....................................
................ X.d2 .lt,grnd f a on river t o f, .................................... ................
Form No. 113l-Aor. U. S. DEPARTMENT OF AGRICULTURE
WEATHER BUREAU
PILOTS WEATHER REPORT
between t8his phenomenon and prevailing weather condi-
tions. No auroras are observed during the summer season, simply because they nre not visible during the
continuous daylight. By the end of July there is a short
period of deep twilight a t midnight, and the brightest stars are once more visible. The darkness rnpidly increases, and 2 weeks lnter the first nurorn may be observed. The
displnys nre frequent from this time until May, when cont,inuous daylight ngnin prevails. During the past 4
years 61ie physics department of the Alnska Agriculturnl Colle,ge near Fairbnnks has been mensuring the height
of the niirorn by menns of simultaneous photographs 8.t stabions nbout 15 miles apart. The general height
ns determined from these measurements ranges between
60 and 200 miles.
EARTHQUAKES
No severe or destructive tre.mors hnve been recorded
in the interior of Alnska. However, the nuniber of
light shoclis avernges eight nnnunlly. The ceii ter of
to this trunk line a few miles of feeder roads, mostly in
the Fairbanks district, have been constructed as the need
nrose. On the high passes the road is blocked by snow
From October to the middle of June each year. When
the Alaska Rnilrond was completed in 1923 the interior country became ensily accessible the year round. The
rnilroad extends from Sewnrd, on the coast, to Fairbanks
a dist8ance of 670 miles. The weekly trains make con-
nections with the steamboats nnd one niay now travel from Sentt,le to Fairbanks in 8 clnys. Upon the comple-
tion of the rnilrond Fnirbnnks became the distributing center for central and western Alaska. Travel and transportation had greatly improved since the pioneer clays n t the beginning of tlie century. However the
interior country is a vast region equd in size to the State of California. With but one road a.nd one railway,
the trans ortntion system was about e ual to that of the Middle $est n t the close of the Civilhar. The intro-
duction of commercial aviation lins brought about won-
derful changes during the last 10 years. The late Col.