...BELOW AVERAGE FLOOD POTENTIAL EXPECTED FOR CALIFORNIA THIS
SPRING...
THE SPRING FLOOD POTENTIAL OUTLOOK IS BELOW AVERAGE FOR ALL BASINS IN
CALIFORNIA. DRY ANTECEDENT SOIL MOISTURE CONDITIONS AND LOW
SNOWPACKS ARE MINIMIZING THE POTENTIAL FOR SPRING SNOWMELT FLOODING.
MUCH OF THE REGION HAS EXPERIENCED VERY DRY CONDITIONS AFTER A VERY
PRODUCTIVE NOVEMBER AND DECEMBER. MANY LOCATIONS HAVE RECORDED
PRECIPITATION AMONG THE TOP TEN LOWEST ON RECORD FOR THE COMBINED
MONTHS OF JANUARY AND FEBRUARY. THIS HAS REDUCED THE STATEWIDE
SNOWPACK WATER CONTENT FROM 134 PERCENT OF AVERAGE NEAR THE START OF
JANUARY TO ABOUT 66 PERCENT FOR THIS TIME OF THE YEAR.
SOME RELIEF OCCURRED DURING THE EARLY PART OF MARCH...MOSTLY IN THE
NORTHERN AND CENTRAL REGIONS OF THE STATE. HOWEVER...IT WILL TAKE A
SERIES OF STRONG STORM SYSTEMS TO RETURN THE SNOWPACK TO NORMAL
CONDITIONS BY APRIL 1ST... WHICH IS THE TYPICAL TIME OF MAXIMUM
SNOWPACK ACCUMULATION. IT APPEARS VERY UNLIKELY THAT SNOWPACKS CAN
RECOVER FROM THE CURRENT DEFICIT THIS LATE INTO THE WET SEASON.
NOTE THAT FLOODING COULD STILL RESULT FROM HEAVY RAINFALL ALONE OR
COMBINED WITH SNOWMELT ANYTIME BETWEEN NOW AND EARLY APRIL.
PRECIPITATION...
FEBRUARY 2013 WATER YEAR
BASIN PERCENT OF AVERAGE PERCENT OF AVERAGE
UPPER KLAMATH 26 105
LOWER KLAMATH 41 79
TRINITY 7 68
EEL RIVER 22 86
RUSSIAN 10 71
NAPA 5 85
SF BAY AREA 18 96
UPPER SACRAMENTO 11 91
CENTRAL SIERRA 13 75
SOUTHERN SIERRA 31 71
CENTRAL COAST
SANTA CRUZ 5 68
PAJARO RIVER 6 40
SALINAS RIVER 8 41
SAN LUIS OBISPO 16 73
SANTA YNEZ 5 38
SOUTH COAST
SANTA BARBARA COAST 4 61
VENTURA LA COASTAL 12 65
SANTA CLARA RIVER 3 37
LOS ANGELES RIVER 5 44
SANTA ANA RIVER 15 44
SAN DIEGO BASIN 24 60
SOUTH EAST DESERTS
OWENS RIVER 3 28
AMARGOSA 0 65
MOJAVE DESERT 25 53
MOJAVE RIVER 28 62
COLORADO RIVER 8 89
WHITEWATER RIVER 29 33
SNOWPACK...
MANUAL SNOW MEASUREMENTS TAKEN BY THE CALIFORNIA COOPERATIVE SNOW
SURVEYS CONFIRM THAT CALIFORNIA`S MOUNTAIN SNOWPACK HOLDS FAR LESS
WATER THAN NORMAL FOR THIS TIME OF YEAR...
PERCENT OF AVG SNOWPACK PERCENT OF AVG SNOWPACK
BASIN MARCH 1 2012 MARCH 1 2013
SAC/NRN SIERRA 27 58
SAN JOAQUIN VALLEY 27 66
TULARE LAKE 34 60
UPPER KLAMATH 67 75
RESERVOIRS...
A BRIGHT SPOT IS THAT STORAGE IN MANY OF CALIFORNIA`S MAJOR
RESERVOIRS IS ABOVE AVERAGE AT THE PRESENT TIME...
PERCENT OF AVG STORAGE
RESERVOIR MARCH 1 2013
SHASTA LAKE 110
LAKE OROVILLE 111
YUBA-BULLARDS BAR 128
AMERICAN-FOLSOM LAKE 103
STANISLAUS-NEW MELONES 114
TUOLUMNE 99
MERCED-LAKE MCCLURE 85
SAN JOAQUIN-MILLERTON LAKE 95
KINGS-PINE FLAT 60
KERN-ISABELLA 41
RUNOFF...
CONTINUING DRY CONDITIONS DURING THE LAST 2 MONTHS IS REFLECTED IN
THE MUCH BELOW AVERAGE RUNOFF CONDITIONS FOR FEBRUARY 28...
FEBRUARY 2013 WATER YEAR
BASIN PERCENT OF AVG RUNOFF PERCENT OF AVG RUNOFF
TRINITY-SACRAMENTO 36 85
SAN JOAQUIN 32 69
TULARE LAKE 34 49
UPPER KLAMATH 53 70
STREAMFLOW FORECASTS...
APRIL THROUGH JULY FORECASTS ARE GENERALLY BELOW TO MUCH BELOW
AVERAGE FOR UPPER SACRAMENTO/WEST-SLOPE SIERRA NEVADA WATERSHEDS IN
CALIFORNIA. THE APRIL THROUGH SEPTEMBER FORECAST FOR THE UPPER
KLAMATH IS ABOUT 83 PERCENT.
TO SUMMARIZE... THE FLOOD POTENTIAL IS BELOW AVERAGE FOR ALL
WATERSHEDS IN CALIFORNIA TYPICALLY AFFECTED BY SPRINGTIME
SNOWMELT...AS WELL AS OTHER REGIONS IN THE STATE WHERE SNOWMELT IS
NOT A MAJOR FACTOR IN SPRINGTIME FLOODING.
