U.S. Geological Survey

U.S. Department of the Interior

Storms and Flooding in California in 

December 2005 and January 2006–

a Preliminary Assessment

Open-File Report 2006–1182
Inside front cover.
Storms and Flooding in California in 

December 2005 and January 2006—A 

Preliminary Assessment

By Charles Parrett and Richard A. Hunrichs

Open-File Report Series 2006–1182

U.S. Department of the Interior

U.S. Geological Survey
U.S. Department of the Interior

Dirk Kempthorne, Secretary

U.S. Geological Survey

P. Patrick Leahy, Acting Director

U.S. Geological Survey, Reston, Virginia: 2006

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reproduce any copyrighted materials contained within this report.

Suggested reference

Parrett, Charles, and Hunrichs, R.A., 2006, Storms and flooding in California in December 2005 and January 2006—A 

preliminary assessment: U.S. Geological Survey Open-File Report 2006–1182, 8 p. 
Contents

Abstract ................................................................................................... 1

Introduction ............................................................................................. 1

Summary of Major Storms .............................................................................. 1

Summary of Flooding .................................................................................... 2

References Cited.......................................................................................... 8

Figures

Figure 1. Map showing rainfall over California and Nevada for (A) December 28, 2005, 

(B) December 31, 2005, and (C) January 2, 2006 .......................................... 2

Figure 2. Map showing location of selected streamflow-gaging stations, precipitation 

stations, and in recurrence interval ranges for peak discharges in California, 

December 2005 and January 2006 ......................................................... 5

Figure 3. Graph showing recorded annual peak discharges for the streamflow-gaging 

station at the Napa River at Napa, California ............................................. 6

Figure 4. Photograph showing flooding from the Russian River along Highway 101 near 

Hopland, California, December 31, 2005 ................................................... 7

Figure 5. Photograph showing streamflow on the South Yuba River passing under old 

Highway 29 Bridge, California, December 31, 2005 ....................................... 8

Tables

Table 1. Precipitation at selected precipitation stations in California, December 24, 2005, 

through January 3, 2006 ..................................................................... 2

Table 2. Peak discharge data for selected U.S. Geological Survey streamflow-gaging 

stations in California........................................................................... 3

iii
Conversion Factors

Inch/Pound to SI

Multiply By To obtain

Length

inch (in.) 2.54 centimeter (cm)

inch (in.) 25.4 millimeter (mm)

foot (ft) 0.3048 meter (m)

mile (mi) 1.609 kilometer (km)

Area

square mile (mi2) 259.0 hectare (ha)

square mile (mi2) 2.590 square kilometer (km2) 

Volume

cubic foot (ft3) 28.32 cubic decimeter (dm3) 

cubic foot (ft3) 0.02832 cubic meter (m3) 

Flow rate

cubic foot per second (ft3/s) 0.02832 cubic meter per second (m3/s)

SI to Inch/Pound

Multiply By To obtain

Length

centimeter (cm) 0.3937 inch (in.)

millimeter (mm) 0.03937 inch (in.)

meter (m) 3.281 foot (ft) 

kilometer (km) 0.6214 mile (mi)

Area

hectare (ha) 0.003861 square mile (mi2) 

square kilometer (km2) 0.3861 square mile (mi2)

Volume

cubic decimeter (dm3) 0.03531 cubic foot (ft3) 

cubic meter (m3) 35.31 cubic foot (ft3)

Flow rate

cubic meter per second (m3/s) 35.31 cubic foot per second (ft3/s)

Water year: The 12-month period October 1 through September 30. It is designated by the calendar year in 

which it ends.

NOTE TO USGS USERS: Use of hectare (ha) as an alternative name for square hectometer (hm2) is 

restricted to the measurement of small land or water areas. 

Acronyms used in this report:

USGS U.S. Geological Survey

FEMA Federal Emergency Management Agency

iv
Abstract

A series of storms beginning before Christmas 2005 and 

ending after New Year’s Day 2006 produced significant runoff 

over much of northern California. The storms resulted in an 

estimated $300 million in damages and Federal disaster declarations in 10 counties. Several precipitation stations in the 

Sierra Nevada had precipitation totals greater than 20 inches 

for the period December 24 through January 3, and several 

stations in the Coastal Range had precipitation totals greater 

than 18 inches. The peak stream discharges resulting from 

the storms in the north coast area generally had recurrence 

intervals in the 10- to 25-year range, although the recurrence 

interval for peak discharge at one station on Sonoma Creek 

near Agua Caliente was greater than 100 years. In the San 

Francisco Bay area, peak discharges also generally had recurrence intervals in the 10- to 25-year range. Further south along 

the central coast and in southern California, peak discharges 

had smaller recurrence intervals, in the 2- to 5-year range. 

Upper Sacramento River tributaries draining from the west had 

peak flows with recurrence intervals in the 2- to 5-year range, 

whereas upper tributaries draining from the east side had 

recurrence intervals in the 5- to 10-year range. Further south, 

Sacramento River tributaries such as the Yuba and American 

Rivers had peak discharges with recurrence intervals in the 

10- to 25-year range. On the east side of the central Sierra 

around Lake Tahoe, peak discharges had recurrence intervals 

in the 10- to 25-year range. Further south in the Sierra, streams 

draining into the San Joaquin River Basin had flows with 

recurrence intervals ranging from 2 to 5 years. 

Introduction 

A series of storms beginning before Christmas 2005 and 

ending after New Year’s Day 2006 produced significant runoff 

over much of northern California, including the north coast 

and the Sierra Nevada. There were localized evacuations and 

flooding, some slope failures, and road closures. An estimated 

$300 million in damages were attributed to the storms (California Office of Emergency Services, 2006). Ten counties subsequently were declared Federal disaster areas: Contra Costa, 

Del Norte, Lake, Marin, Mendocino, Napa, Sacramento, 

Siskiyou, Solano, and Sonoma (Federal Emergency Management Agency, 2006). Major flood damages were concentrated 

primarily in the Napa and Russian River Basins in Napa and 

Sonoma Counties. 

 The flooding was widely compared by the media to 

the floods of 1986 and 1997, although the stream discharges 

generally were significantly smaller than those of the earlier 

floods. A storm on January 1 had been predicted to cause 

problems in southern California also; however, that storm did 

not develop as predicted. Nevertheless, the storm did manage 

to rain on the Rose parade for the first time in 51 years. 

Summary of Major Storms

On the basis of provisional data obtained from the 

National Weather Service, California–Nevada River Forecast 

Center (2006), storm totals recorded by automated rainfall 

recorders at several precipitation stations on the western 

slopes of the Sierra Nevada during the December 24–January 

3 period were greater than 20 inches. In addition, recorders 

at several stations at the headwaters of the Russian and Napa 

River Basins in the Coast Range had storm totals greater than 

18 inches. Storm totals at two selected stations in the Coast 

Range (Willits Howard RS and Venado) and at two selected 

stations in the Sierra Nevada (Brush Creek and Girard) are 

presented in table 1. 

The 3 days of the 7-day period with the most intense 

precipitation were December 28, December 31, and January 

2. Daily precipitation totals were for a 24-hour period 4:00 

a.m. to 4:00 a.m. Precipitation was as much as 4.68 inches on 

December 28 at the Willits Howard RS station. On December 31, the day of most intense rainfall over most of northern 

California, more than 5 inches were recorded at all sites, and 

the Venado and Willits Howard RS stations recorded 6.81 and 

7.12 inches, respectively. Although rainfall intensity on January 2 generally was less than on December 28 and December 

31, as much as 3.84 inches was recorded at Venado. Figure 1

shows the areal distribution and amounts of daily rainfall 

throughout northern California on December 28, 31, and 

January 2. 

Storms and Flooding in California in December 2005 and 

January 2006—A Preliminary Assessment

By Charles Parrett and Richard A. Hunrichs
Summary of Flooding

Unusually warm storms produced more runoff from 

higher elevations than normal for December and January. 

Because the accumulated snow pack had been rather light, 

snowmelt did not significantly increase runoff. Previous large 

floods in northern California, including the most recent in 

1986 and 1997, had significant runoff from snowmelt as well 

as from large storms (Hunrichs and others, 1998; U.S. Geological Survey, 1989).

Table 2 shows recorded peak discharges, gage heights, 

and computed recurrence intervals associated with the peak 

discharges at selected USGS streamflow-gaging stations. The 

peak discharges of record at the sites are also shown. The 

peak-discharge data are from near-real time stations, and the 

data are provisional and may change based on further review. 

As indicated by table 2, five sites, with periods of recorded 

data ranging from 24 to 64 years, had peaks of record (rank 

1) on December 31, 2005. Figure 2 shows the locations of the 

streamflow-gaging stations and the recurrence intervals for 

the December–January peak discharges and the locations of 4 

selected precipitation stations.

Precipitation station

Total precipitation for 

December 24–January 3 

(inches)

Precipitation for 24-hour period (inches)

12/28/06 12/31/06 01/02/06

Sierra Nevada

Brush Creek 22.05 2.75 6.81 2.56

Girad 20.08 3.84 5.04 2.32

Coast Range

Venado 29.60 4.24 6.88 3.84

Willits Howard RS 18.48 4.68 7.12 0.96

Table 1. Precipitation at selected precipitation stations in California, December 24, 2005, through January 3, 2006.

[24-hour period begins at 4:00 a.m.]

Map color indicates precipitation, in inches, as indicated by the color shade bar scale below. Gray shades indicate ‘no data’.

A B C

Figure 1. Rainfall over California and Nevada for (A) December 28, 2005, (B) December 31, 2005, and (C) January 2, 2006. 

(From National Weather Service, California–Nevada River Forest Center, 2006)

   Storms and Flooding in California in December 2005 and January 2006—A Preliminary Assessment
Station 

number Station name

Drainage 

area

(mi2)

Flooding of 

December–

January

Peak 

discharge

(ft3/s)

Gage

height

(ft)

Reccurrence 

interval 

(years)

Rank Years of record

Historic 

alflooding Year

Date of peak 

discharge

Maximum 

peak (ft3/s)

10308200 East fork Carson River below Markleeville Creek 

near Markleeville 

276 12/31/2005 19,300 11.81 25–50 1 44 18,900 1997

10310000 West fork Carson River at Woodfords 65.4 12/31/2005 3,010 14.36 10–25 8 89 8,100 199710336660 Blackwood Creek near Tahoe City 11.2 12/31/2005 2,260 7.43 10–25 2 44 2,940 199710336676 Ward Creek at Hwy 89 near Tahoe Pines 9.7 12/31/2005 1,660 8.44 10–25 3 32 2,530 199710336780 Trout Creek near Tahoe Valley LIF 36.7 12/31/2005 623 9.7 25–50 1 43 535 196310338000 Truckee River near Truckee 553 12/31/2005 6,030 6.97 10–25 5 35 11,900 199710346000 Truckee River at Farad 932 12/31/2005 10,100 10.77 10–25 9 105 17,500 195011098000 Arroyo Seco near Pasadena 16 1/2/2006 1,120 4.58 2–5 26 90 8,620 193811111300 Sespe Creek near Filllmore 251 1/2/2006 20,800 16.5 2–5 19 66 73,000 199811143250 Carmel River near Carmel 247 12/31/2005 3,010 10.55 <2 21 39 16,000 199511147500 Salinas River at Paso Robles 390 1/2/2006 6,950 11.84 2–5 22 59 28,400 199511152000 Arroyo Seco near Soledad 244 12/31/2005 12,900 10.95 2–5 28 99 28,300 195811159000 Pajaro River at Chittenden 1,186 1/3/2006 5,030 19.25 2–5 28 65 25,100 199811161000 San Lorenzo River at Santa Cruz 115 12/31/2005 13,900 21.55 5–10 5 25 30,400 195511162500 Pesdero Creek near Pesdero 45.9 12/31/2005 6,000 15.95 5–10 8 53 10,600 199811164500 San Francisquito Creek at Stanford 

University

37.4 12/31/2005 4,840 10.35 10–25 4 64 7,220 1998

11169500 Saratoga Creek at Saratoga 9.22 12/31/2005 1,120 6.31 5–10 14 71 2,730 195511189500 South fork Kern River near Onyx 530 1/2/2006 1,600 7.54 2–5 23 71 28,700 196611119940 Maria Ygnacio Creek at University Drive near 

Goleta

6.4 1/2/2006 299 2.95 <2 23 33 2,500 1992

11266500 Merced River at Pohono Bridge near Yosemite 321 12/31/2005 10,200 12.54 5–10 10 88 24,600 199711335000 Cosumnes River at Michigan Bar 536 12/31/2005 35,100 13.68 10–25 8 98 93,000 199711336580 Morrison Creek near Sacramento 53.4 12/31/2005 2,420 9.67 10–25 3 35 2,730 198611345500 South fork Pit River near Likely 247 12/31/2005 772 4.69 5–10 9 73 1,620 197111372000 Clear Creek near Igo 228 12/30/2005 4,400 8 2–5 33 64 24,500 195511377100 Sacramento River above Bend Bridge near 

Red Bluff

8,900 12/31/2005 118,000 30.09 <2 40 123 291,000 1940

11379500 Elder Creek near Paskenta 92.4 12/30/2005 7,650 10.93 2–5 15 56 17,700 1983

Table 2. Peak discharge data for selected U.S. Geological Survey streamflow-gaging stations in California.[Rank, position of the December-January peak discharge in a ranked, from largest to smallest, list of all recorded annual peak discharges for the period of record. mi2, square mile; ft3/s, cubic foot per second; ft, foot. <, less than the actual value shown; > actual value is greater than value shown]

Summary of Flooding   
Station 

number Station name

Drainage 

area

(mi2

)

Flooding of 

December–

January

Peak 

discharge

(ft3/s)

Gage

height

(ft)

Reccurrence 

interval 

(years)

Rank Years of record

Historic 

alflooding Year

Date of peak 

discharge

Maximum 

peak (ft3/s)

11383500 Deer Creek near Vina 208 12/31/2005 10,300 11.15 5–10 16 88 24,000 199711390000 Butte Creek near Chico 147 12/31/2005 13,800 9.41 5–10 8 74 35,600 199711413000 North Yuba River below Goodyears Bar 250 12/31/2005 27,200 19.57 10–25 6 74 45,500 199711425500 Sacramento River at Verona 21,251 1/3/2006 85,600 38.72 10–25 3 75 94,000 199711427000 North fork American River at North Fork Dam 342 12/31/2005 51,600 10.48 10–25 5 63 65,400 196411447360 Arcade Creek near Del Paso Heights 31.4 12/31/2005 3,510 15.88 10–25 1 24 3,320 199811456000 Napa River near St Helena 78.8 12/31/2005 18,000 21.61 25–50 1 64 16,900 198611458000 Napa River near Napa 218 12/31/2005 29,600 29.85 10–25 3 48 37,100 198611458500 Sonoma Creek at Agua Liente 58.4 12/31/2005 17,600 32.51 >100 1 29 8,880 195511463000 Russian River near Cloverdale 503 12/31/2005 50,700 26.2 25–50 4 53 55,200 196411467000 Russian River near Guerneville 1,338 1/1/2006 85,800 44.21 10–25 6 65 102,000 198611468000 Navarro River near Navarro 303 12/31/2005 55,700 39.81 10–25 3 54 64,500 195511468500 Noyo River near Fort Bragg 106 12/31/2005 13,700 25.09 5–10 8 53 26,600 197411475560 Elder Creek near Branscomb 6.5 12/31/2005 1,040 7.49 2–5 10 38 3,660 196411476500 South fork Eel River near Miranda 537 12/28/2005 88,400 32.59 5–10 12 64 199,000 196411477000 Eel River at Scotia 3,113 12/31/2005 328,000 52.71 5–10 10 93 752,000 196411481000 Mad River near Arcata 485 12/30/2005 47,300 22.72 5–10 10 57 81,000 196411473900 Middle fork Eel River near Dos Rios 745 12/30/2005 94,700 26.52 10–25 2 39 135,000 199711517500 Shasta River near Yreka 793 12/30/2005 9,320 11.59 25–50 3 69 21,500 196411523000 Klamath River at Orleans 8,475 12/30/2005 216,000 34.8 10–25 5 77 307,000 196411530000 Trinity River at Hoopa 2,853 12/31/2005 108,000 40.68 5–10 10 78 231,000 196411530500 Klamath River near Klamath 12,100 12/31/2005 416,000 47.12 25–50 7 91 557,000 196411532500 Smith River near Crescent City 641 12/30/2005 124,000 29.55 10–25 12 73 228,000 1964

Table 2. Peak discharge data for selected U.S. Geological Survey streamflow-gaging stations in California—Continued.[mi2, square mile; ft3/s, cubic foot per second; ft, foot. <, less than the actual value shown; > actual value is greater than value shown]

   Storms and Flooding in California in December 2005 and January 2006—A Preliminary Assessment
*#

*#

*#

*#

*#

*#

*#

*#

*#

*#

*#

*

*# *#

*#

*#

*#

*#

*#

*#

*# *#

*#

*#

*#

*# *#

*#

*#

*#

*#

*#

*#

*#*#

*#

*#

*#

*#

*#

*#

*#

*#

*#

*#

*#

*#

*#

*#

")

")

")

")

11532500

11530500

11530000

11523000

11517500

11473900

11481000

11477000

11476500

11475560

11468500

11468000

11467000

11463000

11458500

11458000

11456000

11456000

11447360

11425500 11427000

11413000

11390000

11383500 11379500

11377100

11372000

11345500

11336580 11335000

11266500

11266500

11119940 11113000

11189500

11169500

11164500

11162500

11161000

11159000

11159000

11152000

11147500

11143250

11143250

11098000

10346000

10346000

10338000

10336780

10336780

10336676 10336660

10310000

10308200

Venado

Girard

Girard

Brush Creek

Willits Howard RS

EXPLANATION

") Precipitation station and name

Streamflow-gaging station and number

(Recurrence interval, in years)

*# less than 2

*#

*#

2–5

*# 5–10

*# 10–25

*# 25–50

*# greater than 100

0 50 100 Miles

0 50 100 Kilometers

Figure 2. Location of selected streamflow-gaging stations, precipitation stations, and recurrence interval ranges for peak discharges in 

California, December 2005 and January 2006.

Summary of Flooding   
Recurrence intervals, which express the average length of 

time in years between exceedances of peak flood discharges 

as large as those recorded during the December–January flood 

period, provide an indication of the frequency of flooding. For 

example, a peak discharge with a recurrence interval of 10 

years is likely to be exceeded, on average, once every 10 years. 

The reciprocal of recurrence interval is the annual exceedance 

probability of a peak discharge. A peak discharge with a recurrence interval of 10 years has an annual exceedance probability of 0.10, or 10 percent. During any year, the probability of 

having a peak discharge greater than a peak discharge with a 

10-year recurrence interval is 0.10, or 10 percent. 

Flood frequencies (recurrence intervals) for the 

December–January peak discharges were determined by fitting 

a log Pearson Type 3 probability distribution to the period of 

recorded annual peak discharges (through 2004 and including 

the December 2005–January 2006 peak discharge) at each site 

using methods described in Bulletin 17B by the Interagency 

Advisory Committee on Water Data (1982). The floodfrequency analyses were based on regional skew values provided in Bulletin 17B and did not include any adjustments for 

historical floods, high or low outliers, comparison with other 

stations, or other procedures described in the bulletin. The 

flood-frequency analyses also did not account for streamflow 

regulation or land-use changes over time, such as urbanization. 

These recurrence intervals are thus provisional and likely to 

change after a more thorough and rigorous analysis of flood 

frequency in California. The need for updated flood-frequency 

information in California is highlighted by the bar chart in 

figure 3, which shows that the three largest annual peak discharges at the Napa River at Napa (USGS station 11458000) 

were in water years 1986, 1995, and 2006 (December 31, 

2005), after the last (1977) statewide systematic updating of 

flood-frequency data for USGS gage sites (Waananen and 

Crippen, 1977). 

The most commonly used recurrence intervals for 

analyses of peak discharges are 2, 5, 10, 25, 50, and 100 years. 

These recurrence intervals were also used for the December–

January peak discharges analyzed in this study. The intervals 

are presented in table 2 and figure 2 for the following ranges: 

less than 2 years, 2 to 5 years, 5 to 10 years, 10 to 25 years, 25 

to 50 years, and greater than 100 years. 

1986

1995

2006

0

10,000

20,000

30,000

40,000

1930

1935

1940

1945

1950

1955

1960

1965

1970

1975

1980

1985

1990

1995

2000

2005

2010

WATER YEAR

ANNUAL PEAK DISCHARGE, IN CUBIC FEET PER SECOND

Three largest annual peak discharges

(1986, 1997, and 2006) occurred after

last statewide analysis of flood frequency

in California in 1977

year of last flood-frequency analysis

Figure 3. Recorded annual peak discharges for the streamflow-gaging station at the Napa River at Napa, California.

   Storms and Flooding in California in December 2005 and January 2006—A Preliminary Assessment
In the north coast area, the recurrence intervals for the 

peak flows generally were in the 10- to 25-year range. Discharge for some stations, particularly those near the mouth 

of the Klamath River and in the upper Russian River Basin 

(fig. 4), showed more extreme flows, with recurrence intervals in the 25- to 50-year range. The peak discharge for the 

Sonoma River at Agua Caliente (USGS station 11458500) 

had a recurrence interval greater than 100 years and was about 

twice as big as the previous peak of record. Records at this 

site, however, do not include data for the large-flood years of 

1986 or 1997. 

The Russian River at Guerneville (USGS station 

11467000), where significant flooding also occurred, had a 

recurrence interval in the 10- to 25-year range. Other streams, 

particularly those in the Eel River Basin, had less extreme 

peak discharges, with recurrence intervals in the 5- to 10-year 

range. 

Streams in the San Francisco Bay area, including the 

Napa River Basin, had peak discharges with recurrence intervals generally in the 10- to 25-year and 25- to 50-year ranges. 

Along the central coast (Carmel River and Salinas River, for 

example) and in southern California (Sespe Creek and Arroyo 

Seco, for example), recurrence intervals generally were in the 

2- to 5-year range. 

Flows in the mainstem of the Sacramento River stayed 

within the capacity of the flood-control system, as relief weirs 

and bypass channels were brought into operation. The peak 

discharge on the Sacramento River above Bend Bridge near 

Red Bluff (USGS station 11377100), which is regulated by 

Lake Shasta, had a recurrence interval of less than 2 years. 

Unregulated peak streamflows from tributaries draining the 

Coast Range on the west side of the upper Sacramento River 

Basin showed recurrence intervals in the 2- to 5-year range, 

whereas peak discharges from tributary streams draining the 

southern Cascade Mountains and the Sierra Nevada on the east 

side of the Sacramento River Basin had recurrence intervals in 

the 5- to 10-year range. Recurrence intervals for peak discharges from tributary streams farther south in the Sacramento 

River Basin (Yuba River and American River) generally were 

in the 10- to 25-year range (fig. 5). High flows, coupled with 

high tides and high winds, caused problems along levees in the 

Sacramento–San Joaquin River delta. At some locations, wind 

waves overtopped, but did not collapse, levees. Officials noted 

more than 40 episodes of erosion or seepage in the levees. 

On the east side of the central Sierra Nevada around Lake 

Tahoe, these warm storms generally brought runoff peaks with 

recurrence intervals in the 10- to 25-year range. Further south, 

streams draining from the Sierra Nevada into the San Joaquin 

River Basin had peak flows with recurrence intervals ranging 

from 2 to 5 years. 

Figure 4. Flooding from the Russian River along Highway 101 near Hopland, California, December 31, 2005. 

View is looking north. Photograph by Ken Markham, U.S. Geological Survey.

Summary of Flooding 
References Cited

California Office of Emergency Services, 2006, 2005–2006 

winter storms status report, January 9, 2006 as of 1200 

hours: 4 p., accessed February 16, 2006, at http://

www.oes.ca.gov/Operational/OESHome.nsf/PDF/05-

06%20Storm%20Update/$file/05-06WinterStormUpdate.pdf

Federal Emergency Management Agency, 2006, Designated 

counties for California severe storms, flooding, mudslides, 

and landslides: Disaster Summary for FEMA-1628-DR, 

California, 1 p., accessed February 16, 2006, at http://www.

fema.gov/news/eventcounties.fema?id=5925

Hunrichs, R.A., Pratt, D.A., and Meyer, R.W., 1998, Magnitude and frequency of the floods of January 1997 in Northern and Central California—preliminary determinations: 

U.S. Geological Survey Open-File Report 98-626, 120 p.

Figure 5. Streamflow on the South Yuba River passing under old Highway 29 Bridge, California, December 31, 2005. 

View looking upstream. Photograph by Ian O’Halloran.

Interagency Advisory Committee on Water Data, 1982, Guidelines for determining flood flow frequency—Bulletin 17B 

of the Hydrology subcommittee: U.S. Geological Survey, 

Office of Water Data coordination, 183 p.

National Weather Service, California–Nevada River Forecast 

Center, 2006, Heavy precipitation event southwest Oregon, 

northern California, and western Nevada, December 24, 

2005–January 03, 2006: National Oceanic and Atmospheric 

Administration, unnumbered pages, accessed February 16, 

2006, at http://www.cnrfc.noaa.gov/dec2005storms.php

Waaneanen, A.O. and Crippen, J.R., 1977, Magnitude and 

frequency of floods in California: U.S. Geological Survey 

Water-Resources Investigations Report 77-21, 102 p.

U.S. Geological Survey, 1989, National water summary 1988-

89—Floods and droughts: U.S. Geological Survey WaterSupply Paper 2375, 512 p.

   Storms and Flooding in California in December 2005 and January 2006—A Preliminary Assessment