4-20

Delineation Drilling Activities Offshore Santa Barbara County

area at 4:52 a.m. on July 21, 1952. It registered at

magnitude 7.7 and was located on the White Wolf

thrust fault, near the San Andreas fault, about 60

miles (95 km) northeast of Santa Barbara. This quake

was felt over a wide area, including northern California, Nevada, Arizona, and Mexico. The Modified Mercalli intensity rating for this earthquake was X to XI

(Richter, 1958). Widespread damage was evident in

communities near the epicenter, and minor damage

was even noted in cities well removed from the maximum shaking.

At 6:01 a.m. on the morning of February 9, 1971,

a magnitude 6.6 earthquake struck in the eastern portion of the Santa Barbara-Ventura basin. This quake

is known as the “San Fernando” or “Sylmar” earthquake, after the communities most seriously damaged.

The earthquake occurred on a generally west-northwest to east-southeast trending, north-dipping thrust

fault and ruptured to the surface (Jennings, 1994).

The hypocenter of the earthquake is reported at a

depth of over 5 miles (8.4 km) (SCEC website). The

damage caused by this quake has been well reported

and studied. Unusual phenomena were observed during this quake, including accelerometer readings

greater than 1.0 (objects “thrown” into the air by

forces greater than the downward force of gravity)

(Bolt, 1971; K. Piper, personal communication; F.

Langston, personal communication).

The 1971 earthquake occurred on the San

Fernando fault. Although the fault had been recognized prior to the quake, it was not then considered

important. Since that time, significant study has been

made on the structural geology and seismic hazard

potential in southern California (Petersen and

Wesnousky, 1994). Subsequent studies have indicated

that the recurrence interval for earthquakes on the

San Fernando fault is about 200 years (SCEC website).

On January 17, 1994, another destructive earthquake hit the onshore portion of the Santa BarbaraVentura basin. The quake, known as the “Northridge”

earthquake, registered at magnitude of 6.7, with a hypocentral depth of 12 miles (18.4 km). Like the 1971

quake, it was felt over a wide area of southern California. This temblor broke on a previously “unknown”

blind thrust, probably related to the Oakridge fault

system (in fact, the fault had been imaged on proprietary CDP reflection data years earlier, although its

earthquake potential was not assessable).

The 1994 quake was spatially related to the 1971

quake. Aftershock hypocentral data for the two earthquakes indicate that the “... Northridge aftershocks

are cut-off by the San Fernando fault at depths of 5 to

8 km. The north-dipping San Fernando fault may have

prevented the south-dipping Northridge rupture from

reaching the surface” (SCEC website).

The Oakridge trend is well defined west of the

Northridge epicenter. It follows an arcuate trace across

Ventura County and out into the Santa Barbara Channel. The recurrence interval on the Oakridge system

has not yet been determined.

4.1.2.2 TSUNAMIS

Tsunamis are potentially destructive ocean

waves formerly called “tidal waves.” A more appropriate description may be “seismic sea waves,” because

of their association with large earthquakes. It is generally believed that large-scale, underwater block

movements, slumps, or slides are the mechanisms for

generating these waves. (Certainly unusual events

such as volcanic island explosions and meteorite impacts are known to have occurred; however, the likelihood of such a wave affecting the southern California

coastline is remote.)

Tsunamis are usually apparent only at the coastline. Due to their long wavelength and low amplitude,

they are rarely noted in deep water. However, in

deepwater conditions they can travel at velocities of

over 600 miles per hour (270 meters per second). As a

tsunami approaches and strikes the coast, the wavelength becomes attenuated and the amplitude grows.

The first sign of an impending tsunami is sometimes

a sudden recession of the ocean away from the coast.

Most tsunamis are generated on the margins of

the Pacific Ocean basin. Consequently, small, transPacific tsunamis strike the California coastline with

regularity. Large tsunamis striking the California

coast are rare. Only three known tsunamis have been

locally generated. The information below is provided

from the National Weather Service website. The reader

is directed there for greater detail.

Associated with the December 21, 1812 earthquake, a tsunami was described at several places along

the north and south shores of the Santa Barbara Channel. Over the years, the height, run up, and damage

caused by this tsunami has been exaggerated and misinterpreted. Little or no physical evidence remains

from the 1812 event.

Contemporary accounts of the tsunami lack specific details. One 1856 account documents a fur-trading vessel being carried inland by the waves at Gaviota

Canyon on the Refugio Rancho upwards to 2,500 feet,

before being taken back out to sea with the receding

water. Similar accounts have ocean water running up

into the plaza at Santa Barbara. These stories might

suggest a maximum height of 50 feet for the 1812 tsunami. A secondhand story from a memoir of an elderly resident of Ventura relates that an old church, 15

feet above sea level, was damaged in 1812. More recent analysis discounts the 50-foot reports and suggests a 10-15 foot wave was more likely.

Complicating the story of the November 21, 1812
4-21

Description of the Affected Environment: Geology

tsunami is a report that a member of the Hawaiian

royal family was killed by a tsunami on that date.

Estimates of the Hawaiian tsunami run up are placed

at 10 feet. If the California earthquake spawned this

wave, then earlier accounts of large waves in the Santa

Barbara Channel have more validity.

A small earthquake, felt only in the Santa Barbara area in late May, 1854, may have been responsible for a “heavy swell” which washed into the town

very soon afterward. The quake quite possibly triggered a nearby submarine slide, which in turn, generated the wave.

On May 10, 1877, a destructive earthquake in

northern Chile generated a tsunami that was monitored around the Pacific basin. At Gaviota, a series of

three 12-foot waves were reported.

On November 22, 1878, a probable tsunami unrelated to any recorded earthquake struck the north

Santa Barbara County and San Luis Obispo County

coastline. This wave was reported to have severely

damaged the Point Sal wharf and the Avila wharf, and

to have washed over the sand bar at Morro Bay. Given

that no earthquakes are reported on that date anywhere around the Pacific basin, this wave may likely

have been locally generated by a large-scale submarine landslide.

On March 9, 1895, an unusual event in Cuyler’s

Harbor, at San Miguel Island, was responsible for the

capsizing of a vessel anchored there. Apparently, a

large portion of the bluffs on the west side of the harbor

slumped in the ocean. The resultant wave rolled the vessel.

The 1927 earthquake off Point Arguello (see

above) generated a small tsunami that was witnessed

by several coastal residents and recorded on tide

meters. The tsunami caused damage to train tracks

at the former community of Surf, near the mouth of

the Santa Ynez River. The waves measured a maximum of 6 feet at Surf, and 4 feet at Pismo Beach.

It is unclear if the 1927 tsunami was generated

by the tectonic forces of the earthquake, or was a result of a submarine landslide associated with the

quake. Two ships’ captains, when interviewed about

the “sea quake,” indicated they had felt in their ships

two distinct events about 20 minutes apart; the second even reported as being “more strongly felt.” The

first event was the main shock of the November 4

earthquake. Seismographs do not record a significant

aftershock at the time of the second reported event.

The captain of another vessel reported aftershocks at

sea about 10:30 a.m. and noted large quantities of dead

or stunned fish at the surface soon thereafter.

It is clear from the record that the 5:51 a.m.

earthquake disrupted the ocean surface of an otherwise “smooth” sea. The evidence suggests that the

main shock triggered an underwater landslide offshore

from Surf. The fish kill may be related to the initial

shock wave of the quake, or to the turbidity and violent turbulence caused by the postulated submarine

landslide. The area of the earthquake is also known

for submarine oil and gas seeps, and it is possible that

a slide may have triggered a toxic release of shallow

methane gas. The lack of a significant aftershock recorded at 6:10 a.m. was initially attributed to a shallow focus event (Byerly, 1930). In fact, the 6:10 event

could have been the progression of a submarine slide

near the ship that had reported its position as 14 miles

north of Point Arguello.

In retrospect, the November 4, 1927 tsunami was

very similar in appearance and location to the November 22, 1878 tsunami. The 1927 event was recorded

by instruments and several witnesses, and remains

the best analogue for a locally derived tsunami with

the project area. Satake and Somerville (1992) suggest that the tsunami was spawned near the epicentral site of Helmberger (1992).

The deadly April 1, 1946 “Scotch Cap” tsunami

became the textbook example for Pacific-wide tsunamis spawned by an Aleutian earthquake. This tsunami

was recorded, by inference, at about 100 feet at the

Scotch Cap Lightstation on Unimak Island. The

progress of the tsunami was well recorded as it sped

southward. Heavy damage was noted at other places

in the Aleutian archipelago and in Hawaii. By the time

the tsunami reached southern California it varied in

height from 5 to 8 feet. At Point Arguello the tsunami

was report as a “seven foot rise.” It appears likely that

the tsunami damage at Unimak Island was exacerbated by a large submarine landslide (Fryer, et al.,

2000).

The very large May 22, 1960 earthquake of the

coast of Chile (the strongest earthquake ever measured on a seismometer M=8.6) generated a long period tsunami that was recorded in southern California. At Santa Barbara Harbor, the initial swell rose 8

feet above the expected tide and then dropped 9 feet

in the course of ten minutes.

The large March 28, 1964 “Good Friday” earthquake (M=8.4) in Alaska generated a series of seismic sea waves that were recorded around the Pacific

basin. Substantial tsunami damage occurred in communities thousands of miles from the earthquake

epicenter. At Morro Bay a ten-foot tide change occurred over a ten-minute interval. In Santa Barbara

“five-foot surges on twenty-minute cycles” were noted.

Tsunamis, although not a common occurrence

along the southern California coast, do pose a potential geologic hazard to coastal communities and facilities. Facilities located in offshore, deep-water areas

(such as oil production platforms) are unlikely to be

affected by tsunamis.
4-22

Delineation Drilling Activities Offshore Santa Barbara County

4.1.2.3 MASS WASTING

“Mass wasting” is a general term that describes

the large-scale movement of rock or earth material

down slope, by gravity, in either a sudden or slow process. Mass wasting can include soil or bedrock creep,

rockfalls, landslides, flows and slumps, and avalanches.

Submarine wasting processes are not well understood

and are rarely witnessed. Prior to the 1960’s, these

processes were inferred to exist due to damage caused

to submarine telephone and telegraph cables. Also,

fishermen and divers reported changes in the ocean

floor topography. These changes were sometimes associated with water discoloration and seismic activity.

More recently, the advent of side-scan sonar and

multibeam technologies has allowed scientists to see

modern submarine landforms. Greene, et al. (2000),

have mapped large-scale slumps off the coast from

Goleta. They conclude that failures such as these have

the potential to generate local tsunamis. Scientists are

not yet able to accurately assess the risks associated

with submarine mass wasting. The ability of catastrophic slope failures to generate tsunamis, or tsunami-like waves, is recognized, as is a causal relationship with seismicity. However, identifying areas prone

to this sort of failure, and determining the likelihood

of such failure, is another matter.

4.1.2.4 SEEPAGE AND SHALLOW GAS

Seepage of oil, tar, or natural gas does not normally present a geologic hazard. Such seepage is evidence that thermally mature source rocks exist in the

area. Seepage is also evidence of the migration of hydrocarbons from the source rock to the surface and is

commonly associated with faulting (the fault acting

as a conduit for the seepage). The seepage of hydrocarbons is usually attributed to the difference in density of oil and natural gas to the connate water that

fills the pore spaces of rocks. The less dense hydrocarbons tend to “rise” through the rock column,

through interconnected pores, along fractures, or by

way of faults, until they are trapped in a sealed reservoir or emanate at the earth’s surface.

In the Santa Barbara Channel area, seepage has

been associated with both fault trends and anticlinal

trends (Fischer, 1978). Some of the most prolific areas of oil, tar, and natural gas seepage occur in the

vicinity of Coal Oil Point, near Santa Barbara. Several studies have attempted to measure or estimate

the volume of seepage in the Santa Barbara Channel

area (Emery, 1960; Vernon and Slater, 1963; Vedder,

et al., 1969; Allen, et al., 1970; Wilkinson, 1972;

Fischer, 1978; Hornafius, et al., 1999; Quigley, et al.,

1999).

Fischer (1978), estimates that between 40 and

670 barrels of oil per day naturally seep into the Santa

Barbara Channel. At one location, near Platform Holly,

two submarine tents have been used since 1982 to trap

gas and oil seepage emanating from the ocean floor.

Since installation, the seep containment structures

have captured in excess of 6 billion cubic feet of gas

from an area of 20,000 square feet. There are no reliable estimates for the total amount of gas seeped into

the Santa Barbara Channel, nor are there any reliable estimates for the volume of oil, tar, or gas seepage north of Point Arguello.

No active seeps of oil, tar, or natural gas have

been identified on the specific leases included in the

proposed action. However, geologic conditions favorable to the formation of hydrocarbon seeps (mature

source rocks, faulting and folding of the strata, erosion of overburden, etc.), and the proximity of the

project areas to known seeps, suggest that natural

seepage can not be entirely ruled out. Reports of oil

sheens and floating tar balls in or near the project

areas may be attributable to several other sources

other than local seepage.

Hornafius, et al. (1999) has suggested that the

annual amount of hydrocarbon seepage in the Santa

Barbara Channel has decreased over time and that

the decrease is associated with sustained offshore oil

and gas production. According to this model, local oil

and gas seepage is due, in part, to hydrocarbons expelled under pressure from subterranean reservoirs.

As compared to the density separation model, this

model contemplates active reservoir recharge, piezometric connectivity, leaky reservoir seals, and ample

conduits from the reservoir to the earth’s surface. As

reservoir pressure is decreased through the production of oil and gas, the driving energy behind the abundant seepage is also decreased, and therefore the

amount of oil and gas emanating at the surface decreases. The result of such a decrease in seepage could

have profound impacts on the amount of natural tar

on local beaches and of reactive hydrocarbons in the

atmosphere.

The Hornafius, et al. (1999) model attempts to

explain the apparent decrease in seepage volumes in

the Santa Barbara Channel over the past 40 years.

Data from the South Ellwood seep containment project

collected since 1982 confirms the decrease at that location. Additional study needs to be conducted to determine whether this is a localized phenomenon, or

whether this model describes a more widespread process.

Shallow gas can present a geologic hazard. This

type of accumulation is often imaged on high-resolution seismic data. Generally, shallow gas accumulations, especially those formed from the natural process of organic decay (biogenic methane), are contained

in low pressure sand reservoirs or surfacial sediments.

However, thermogenic gas (gas produced by time, temperature, and organic maturation) has the potential

to accumulate in “over-pressured” zones that present
4-23

Description of the Affected Environment: Climate

a drilling hazard. High pressure, shallow gas has been

noted in several areas in the Santa Barbara-Ventura

Basin. The giant Ventura Avenue field was discovered

on the basis of shallow gas reservoirs. Hazards posed

by high-pressure shallow gas have been mitigated in

the drilling process by the use of casing and weighted

drilling mud.

4.2 CLIMATE AND METEOROLOGICAL

CONDITIONS

GENERAL DESCRIPTION

The proposed exploration projects are located in

the Outer Continental Shelf (OCS), offshore of Santa

Barbara County within the South Central Coast Air

Basin. Santa Barbara County is considered to be a

Mediterranean climate. It is characterized by partly

cloudy, cool summers without significant precipitation

and mostly clear, mild winters during which precipitation falls with seasonal storms. The climate is

strongly influenced by a persistent high-pressure area

which lies off the Pacific Coast referred to as the Pacific High. The combination of the Pacific High over

the ocean to the west, thermal contrasts between land

and the adjacent ocean, and topographic factors result in the mild temperatures experienced throughout the year.

The topography plays a factor in the wind flows

observed in the county. The change in orientation of

the eastward turn in the coastline at Point Conception and the mountains along the coast, results in a

wind regime characterized by relatively light sea

breezes in the afternoon and strong downslope winds

at night. These terrain features can cause counterclockwise circulation (eddies) to form east of the Point

and may often lead to highly variable winds along the

southern coastal strip. The coastline mountain range

causes a decrease in the occurrence of northwest winds

in the channel as compared with Point Conception,

which marks the change in the prevailing surface

winds from northwesterly to southwesterly.

Transport of cool, humid marine air onshore by

these northwest winds cause fog and low clouds near

the coast, primarily during the night and early morning hours in the late spring and early summer. This

fog also typically forms on the coast and inland valleys during the evening. Fog usually lifts and low

clouds evaporate as land areas are warmed in the

morning. Afternoon conditions are generally characterized by fair skies, cool temperatures, and a sea

breeze. The Pacific High diverts extratropical storms

to the north, and precipitation occurs infrequently

when tropical moisture is transported into the region.

The Pacific High weakens and migrates southward during winter. During the winter season, three

weather regimes generally prevail:

(1) periods of low clouds/fog associated with dominance of the Pacific High;

(2) periods of clear skies, cool nights, and warm

days associated with continental flow; and

(3) periods of variable cloudiness, shifting and

gusty winds, and precipitation associated with

extratropical storms.

An additional component in providing air flow

up the channel from Los Angeles is the eddy low which

is often present in the Southern California Bight.

Under certain conditions this eddy, often referred to

as the Catalina Eddy, will expand and/or shift northward producing a southeasterly gradient in the channel. This may result in a short duration sea breeze

appearing for a short time during the afternoon. However, with a well developed eddy low, surface winds

will remain from the southeast all day.

WIND SPEED AND DIRECTION

The airflow around Santa Barbara county plays

an important role in the movement of pollutants. In

the northern portion of Santa Barbara County (considered north of the ridgeline of the Santa Ynez Mountains), the sea breeze is typically northwesterly

throughout the year while the prevailing sea breeze

in the southern portion are typically from the southwest. During summer months, these winds are stronger and persist later into the night. The sea breeze

weakens during the evening hours as air adjacent to

the surface cools, descending down the coastal mountains resulting in light land breezes (from land to sea).

This land/sea breeze cycle combined with local topography greatly influence the direction and speed of the

winds throughout the county. In addition, the alternation of the land-sea breeze cycle can sometimes produce a “sloshing” effect, where pollutants are swept

offshore at night and subsequently carried back onshore during the day. This effect may be exacerbated

during periods when wind speeds are low.

Data from all the meteorological stations within

the area indicate a general northwesterly flow with

higher wind speeds occurring offshore and at Point

Conception and Point Arguello. The data in the channel generally show a greater westerly component than

do winds at Point Arguello and north, because of the

effects of the east-west oriented Santa Ynez Mountains. Wind data measured at Point Conception, Point

Arguello and Vandenberg all show generally similar
4-24

Delineation Drilling Activities Offshore Santa Barbara County

directional distributions. The data generally reflect

conditions at the proposed exploration locations. However, the average speeds at Vandenberg are somewhat

lower. Therefore, it is reasonable to expect a higher

frequency of pollution events in the southern portion

of the county where light winds are frequently observed, in relation to the North County where the prevailing winds are strong and persistent.

Figure 4.2-1 displays typical prevailing wind

flows during the summer months for the region. The

diagram shows that the generally northwesterly airflow associated with the Pacific High is significantly

modified by interaction with the terrain. The flow

becomes modified at particular times of the day due

to temperature contrasts between the land and the

ocean, resulting in the typical sea breeze experienced

during summer days. The sea-breeze experienced in

Santa Barbara County is common to all of California.

These winds generally carry pollutants generated in

the coastal areas to areas well inland. Typically, the

air quality measured in the coastal areas of California

is much better than that experienced inland.

Upper-level winds in the atmosphere are also important in the air quality of Santa Barbara County.

These winds are routinely measured at Vandenberg

Air Force Base once each morning and afternoon. The

winds at 1,000 feet and 3,000 feet are generally from

the north or northwest throughout the year. Occurrences of southerly and easterly winds are most frequent in winter, especially in the morning. Upperlevel winds from the southeast are infrequent during

the summer, though when they do occur, they are usually associated with periods of high ozone levels. As

with the surface winds, upper-level winds can move

pollutants that originate in other areas into the county.

During the fall and winter months, Santa Barbara County is occasionally subjected to Santa Ana

winds. These are warm, dry, strong, and blustery

winds blown from the high inland desert, through

mountain valleys and eventually out to sea. Wind

speeds associated with Santa Ana conditions are generally 15-20 mph, though speeds in excess of 60 mph

have been registered. During these Santa Ana conditions, pollutants emitted in the Los Angeles region,

Figure 4.2-1. Typical prevaling afternoon summer wind flows.
4-25

Description of the Affected Environment: Climate

occasionally record higher ozone concentrations than

sites at lower elevations.

Atmospheric soundings at Vandenberg Air Force

Base demonstrate that surface inversions (0-500 ft)

are most frequent during the winter, and subsidence

inversions (1000-2000 ft) are most frequent during

the summer. Vertical dispersion of pollutants will

generally be the most inhibited with a lower inversion base height and the greater the rate of temperature increase from the base to the top. The subsidence inversion is common during summer months

along the California coast, and is one of the principle

causes of air stagnation and poor air quality.

TEMPERATURE

The Mediterranean climate characteristic of

Santa Barbara County result in mild temperatures

occurring throughout the year, particularly adjacent

to the coastal regions. Maximum summer temperatures average 70 degrees Fahrenheit near the coast

and in the high 80s to low 90s inland. During winter,

average minimum temperatures range from the 40s

along the coast to the 30s inland. Temperatures within

the coastal region are influenced by the marine dominance of the Pacific Ocean, while more inland areas

of the county exhibit a more continental influence.

Santa Barbara and Santa Barbara Airport, on

the south-facing coast between the ocean and the south

slopes of the Santa Ynez Mountains, experience higher

maximum temperatures, lower minimum temperatures, and more continental influence than those experienced at offshore Platforms and Islands dominated

by marine influences (Table 4.2-1). At Santa Barbara,

the highest mean maximum temperature (79o

F) occurs in September, and the lowest mean minimum

temperature (40oF) occurs in January. Temperatures

Table 4.2-1. Temperature and precipitation data for selected Santa Barbara locations.

Ventura and Santa Barbara Counties are moved out

to sea. These pollutants can then be transported back

onshore into Santa Barbara County (via the Santa

Barbara Channel) in what is called a “post Santa Ana

condition”.

“Sundowner” winds are a local condition inherent to the coastal strip below the Santa Ynez Mountains in Santa Barbara.” These winds are similar in

effect to Santa Ana winds as the condition can produce high intensity, hot northerly winds down canyons and out to sea. While this condition can affect

the local climate (usually for short periods of time),

Sundowners are contrasted by the Santa Ana condition in that the winds are more localized and are

caused by diurnal and land/sea temperature variations.

STABILITY AND MIXING HEIGHT

Stability is an atmospheric trait that influences

the mixing of air. In general, when the atmosphere

becomes less stable, increased turbulence and mixing

of the upper and lower atmosphere are prevalent. The

mixing height is the height of the atmospheric layer

measured from the ground upward in which convection and turbulence promote mixing. Good ventilation and dispersion result from a high mixing height,

unstable conditions, and moderate to high wind speeds

within the mixed layer.

Atmospheric stability is the primary factor that

affects the concentrations of pollutants in the region.

Atmospheric stability regulates the amount of mixing

of air, both horizontally and vertically. An increased

level of atmospheric stability that restricts mixing and

low wind speeds are generally associated with higher

pollutant concentrations. These conditions are typically related to temperature inversions that cap the

pollutants that are emitted below. Inversions are characterized by a layer of warmer air above cooler air

near the ground surface. In an inversion, the temperature of the air layer atypically increases with altitude acting like a cap on the cooler air mass below,

preventing the dispersion of pollutants that are

trapped in the lower air mass. Ozone concentrations

are generally higher directly below the base of elevated

inversions than they are at the ground surface. For

this reason, elevated monitoring sites will

Location Temperature ( F) Precipitation (inches) 

Average 

Maximum 

Average 

Minimum 

Average Annual 

Santa Barbara 71.2 50.1 17.0 

Santa Barbara Airport 69.5 48.7 15.9 

Lake Cachuma 76.9 45.3 18.7 

Lompoc 69.9 46.8 14.0 

Santa Maria 68.7 45.8 12.4 

Source: Western Regional Climate Center 
4-26

Delineation Drilling Activities Offshore Santa Barbara County

at Santa Barbara Airport are slightly cooler. Cold air

drainage off the mountain slopes contributes to the

lower minimum temperature during the winter.

PRECIPITATION

The climate of Santa Barbara is strongly influenced by a persistent high pressure area which lies

off the Pacific Coast. As a result, sunny skies are common throughout most of the area. The majority of

the annual precipitation amounts occur mostly from

October to April, when the Pacific High pressure system has shifted south. Annual rainfall amounts range

from about 10 to 18 inches along the coast, with more

substantial amounts in the higher elevations. On occasion, tropical air masses produce rainfall during the

summer. Cool, humid, marine air causes frequent fog

and low clouds along the coast, generally during the

night and morning hours in the late spring and early

summer. The fog and low clouds can persist for several days at a time until broken up by a change in the

weather pattern.

Average annual precipitation varies markedly

over relatively short distances within the region, primarily because of topographic effects. Relatively high

elevation stations (San Marcos Pass, Gibraltar) in the

Santa Ynez Mountains receive an average of more than

25 inches of precipitation per year (Table 4.2-2). Santa

Barbara receives slightly more precipitation (17.0

inches) than Santa Barbara Airport (15.9 inches).

Historical precipitation levels in the region may

vary widely from year to year. At Santa Barbara, annual precipitation is 8.7 inches or less about once every 10 years; it can also be more than 28 inches one

year in 10 (National Regional Climate Center, 2000).

Table 4.2-2. El Niño 1997 - 1998 precipitation data for Santa Barbara county.

SEVERE WEATHER

Thunderstorms in the project area are infrequent. Fewer than three occur annually at Santa

Barbara Airport (U.S. Naval Weather Service, 1969).

Thunderstorms in the area are generally associated

with active cold fronts or cold lows in winter or with

the transport of tropical moisture into the region in

late summer or early fall.

The winter of 1997-1998 was one of the most

severe winters in local history as the effects of the El

Nino were felt across Southern California. Rainfall

totals resulting from the El Nino for Santa Barbara

County were 273% of normal rainfall for the county

with many stations recording new seasonal records

(National Weather Service, 2000). Table 4.2-2 depicts

a precipitation summary for meteorological stations

in Santa Barbara County as a result of the 1997 -1998

El Nino severe storm cycle.

Rosenthal [1972] reported on occurrences of

other types of severe weather in the region. He indicated that tornadoes are rare in California, with an

estimated return period for a tornado striking the

same location of 1 in 20,000 years for the Los Angeles

area and about the same in other parts of the State.

He also reported that water spouts, though infrequent,

have been sighted over the Santa Barbara Channel.

Remnants of tropical storms formed off the West

Coast of Central America have affected this region on

more than one occasion. However, winds and precipitation associated with these storms have been only

moderate (National Oceanic and Atmospheric Administration, 1976-1978).

Location ’97 - ’98 

Rainfall 

(inches)

Seasonal Record 

(year) 

(inches) 

Normal 

Rainfall 

(inches) 

Percent 

Of Normal 

Cuyama 21.50* 15.56 (68-69) 8.01 268 

Gibraltar Dam 68.85* 64.79 (82-83) 25.37 271 

Lake Cachuma 53.39* 43.90 (82-83) 18.73 285 

Lompoc 37.25* 32.78 (82-83) 13.95 267 

San Marcos Pass 73.87 78.48 (82-83) 26.62 277 

Santa Barbara 46.99* 45.21 (40-41) 16.98 277 

Santa Maria 32.58* 30.73 (40-41) 12.36 264 

Source: National Weather Service 

* seasonal record 
4-27

Description of the Affected Environment: Air Quality

Pollutant Averaging Federal Standards

Time

California Standards

Primary Secondary

1 hour 0.09 ppm (180 μg/m3

) 0.12 ppm (235 μg/m3) Same as Primary

Standard

Ozone (O3)

8 hour -- 0.08 ppm (157 μg/m3

) Same as Primary

Standard

1 hour 20.0 ppm (23 mg/m3) 35.0 ppm (40 mg/ m3) Carbon Monoxide --

(CO) 8 hour 9.0 ppm (10 mg/m3) 9.0 ppm (10 mg/ m3) --

1 hour 0.25 ppm (470 μg/m3) Nitrogen Dioxide --

(NO2) Annual Avg. -- 0.053 ppm (100

μg/m3)

Same as Primary

Standard

1 hour 0.25 ppm (655 μg/m3) -- --

3 hour -- -- 0.5 ppm (1300 μg/m3)

24 hour 0.04 ppm (104 μg/m3) 0.14 ppm (365 μg/m3) --

Sulfur Dioxide

(SO2)

Annual Avg. -- 0.030 ppm (80 μg/m3) --

30 day avg. 1.5 μg/m3 Lead -- --

Calendar qtr. -- 1.5 μg/m3 Same as Primary

Standard

24 hour avg. 50 μg/m3 150 μg/m3 Particulate Matter

(PM10) Annual Avg. 30 μg/m3 50 μg/m3

Same as Primary

Standard

24 hour None 65 μg/m3 Particulate Matter

(PM2.5) Annual Avg. None 15 μg/m3

Same as Primary

Standard

Sulfates 24 hour 25 μg/m3 -- --

Hydrogen Sulfide 1 hour 0.03 ppm (42 μg/m3) -- --

Vinyl Chloride 24 hour 0.010 ppm (26 μg/m3) -- --

Table 4.3-1. Ambient Air Standards

1997 1998 1999

Location

Maximum

 Conc.

Days Above

Standard a Maximum Conc.

Days Above

Standard

Maximum

 Conc.

Days Above

Standard

State Fed. State Fed. State Fed.

Ventura 0.108 2 0 0.091 0 0 0.090 0 0

Ojai 0.106 10 0 0.112 13 0 0.113 7 0

Santa Barbara -

West Carillo St.

0.098 2 0 0.094 0 0 0.098 1 0

Goleta - Fairview 0.091 0 0 0.095 1 0 0.103 1 0

Las Flores Canyon - #1 0.137 5 1 0.130 5 1 0.135 1 1

Gaviota - West 0.087 0 0 0.054 0 0 0

Santa Ynez - Airport Rd. 0.099 1 0 0.104 2 0 0.090 0 0

El Capitan Beach 0.087 0 0 0.099 1 0 0.088 0 0

Santa Maria - Broadway 0.069 0 0 0.073 0 0 0.070 0 0

Santa Rosa Island 0.081 0 0 0.082 0 0 0.093 0 0

National Standard 0.12 ppm, California Standard 0.09 ppm.

a The number of days that at least one measurement was greater than the level of the hourly standard. The number

of days above the standard is not necessarily the number of violations of the standard for the year.

Source: California Air Resources Board

Table 4.3-2. Ozone Monitoring Summary of Representative Monitoring Sites In Ventura and Santa

Barbara Counties