Flood Potential Outlook
Issued by NWS Reno, NV

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NVZ001>041-CAZ070>073-CAZ519>527-170000-

WATER SUPPLY OUTLOOK
NATIONAL WEATHER SERVICE RENO NV
1035 PM PST TUE FEB 10 2015

...WATER SUPPLY OUTLOOK FOR NEVADA AND EASTERN CALIFORNIA AS OF
FEBRUARY 10 2015...

ISSUED JOINTLY BY THE NATIONAL WEATHER SERVICE AND NATURAL RESOURCES
CONSERVATION SERVICE...

1/SUMMARY...WATER SUPPLY OUTLOOK...
THROUGH EARLY JANUARY NORTHERN NEVADA HAD REAPED THE BENEFITS OF
NEAR TO SLIGHTLY ABOVE AVERAGE PRECIPITATION SINCE THE START OF
OCTOBER.  HOWEVER...MUCH OF THE SIERRA NEVADA...FAR WESTERN NEVADA
AND THE LOWER ELEVATIONS OF EASTERN NEVADA WERE MISSED BY THE
PRECIPITATION THAT BOOSTED THE NORTHERN PART OF THE STATE.  EVEN
WITH INCREASED PRECIPITATION IN SOME PARTS OF THE REGION...THE
PRECEDING THREE YEARS HAVE LEFT RAINFALL DEFICITS OVER MUCH OF THE
AREA.  IN SOME PARTS OF WESTERN NEVADA AND THE SIERRA NEVADA
MOUNTAINS UP TO 1 FULL YEAR OF PRECIPITATION HAS BEEN MISSED IN THE
LAST THREE YEARS. A STORM IN MID DECEMBER DID BRING AN INCREASE IN
SOIL MOISTURE FOR PARTS OF THE AREA...BUT HIGH SNOW LEVELS DID
LITTLE TO BOOST THE MIDDLE AND LOW ELEVATION SNOW PACK.

THEN THE MONTH OF JANUARY TURNED OFF WELL BELOW NORMAL IN TERMS OF
PRECIPITATION AND HAD LONG STRETCHES OF WELL ABOVE NORMAL
TEMPERATURES. THIS COMBINATION OF NO PRECIPITATION AND MILD
TEMPERATURES WORKED TO DRASTICALLY DECREASE THE SNOW PACK IN WESTERN
NEVADA WHILE EASTERN NEVADA SAW DECREASES AS WELL...JUST NOT AS
SEVERE. THE DECREASED PRECIPITATION AND MILD TEMPERATURES ALSO
HELPED TO INTENSIFY DROUGHT CONDITIONS ACROSS WESTERN NEVADA.

BY EARLY FEBRUARY SOIL MOISTURE WAS IN LINE WITH EARLY JANUARY
DESPITE THE DRY MONTH AND WERE STILL SLIGHTLY ABOVE LAST YEAR`S
READINGS. SOIL MOISTURE CONTINUES NEAR TO ABOVE NORMAL IN THE LAKE
TAHOE...TRUCKEE...CARSON...WALKER...LOWER HUMBOLDT...NORTHERN GREAT
BASIN...OWYHEE...SNAKE...CLOVER VALLEY AND LOWER COLORADO BASINS.
THE UPPER HUMBOLDT SAW A DECREASE IN SOIL MOISTURE FROM AROUND 41
PERCENT IN JANUARY TO 32 PERCENT IN FEBRUARY.

THE REDUCED SNOWPACK IN THE SIERRA NEVADA MOUNTAINS AND FAR WESTERN
NEVADA ARE LIKELY TO RESULT IN REDUCED RUNOFF LATER THIS SEASON AS
THE SOILS WILL NEED TO BE SATURATED BEFORE SIGNIFICANT RUNOFF
OCCURS. AGRICULTURAL INTERESTS THAT DEPEND ON WATER FROM WINTER
SNOWS AND SPRING RUNOFF WILL NEED TO BE PROACTIVE IN MANAGING WATER
RESOURCES THIS YEAR. ACROSS FAR NORTHERN NEVADA THE INCREASED SOIL
MOISTURE MAY PROMOTE MORE RUNOFF.

RESERVOIR STORAGE REMAINS VERY LOW AS WELL...SO THERE IS LESS WATER
TO DRAW ON FROM PREVIOUS YEARS. WATER USERS THAT DEPEND ON THIS
STORAGE WILL ALSO NEED TO PREPARE FOR POTENTIALLY EXCEPTIONALLY DRY
CONDITIONS.

SMALL SNOWPACKS TEND TO RESULT IN AN EARLIER MELT AND GENERATE LESS
STREAMFLOW AND LOWER PEAK FLOWS THAN NORMAL OR ABOVE NORMAL SNOW
PACKS.

AS OF EARLY FEBRUARY...STREAMFLOW FORECASTS ARE EXPECTED TO
BE WELL BELOW TO MUCH BELOW AVERAGE FOR EASTERN NEVADA...WESTERN
NEVADA AND EASTERN CALIFORNIA THIS SPRING AND SUMMER UNLESS SNOWPACK
CONDITIONS IMPROVE. IN NORTHERN AND NORTH CENTRAL NEVADA STREAMFLOW
FORECASTS ARE EXPECTED TO BE SLIGHTLY BELOW AVERAGE.

THE NEXT SIX TO EIGHT WEEKS WILL BE CRITICAL FOR SNOWPACK THIS
WINTER...AND WHAT THE SPRING AND SUMMER STREAMFLOWS WILL BE. JUST A
FEW WET STORMS WITH LOW SNOW LEVELS WOULD RESULT IN IMPROVED
CONDITIONS.

2/SNOWPACK...
SNOWPACK AS OF FEBRUARY 1ST IN THE SIERRA NEVADA IS WELL BELOW
AVERAGE WITH MUCH OF THE GROUND BELOW 7000 FEET BARE. LAKE TAHOE`S
SNOWPACK SAT AT 17 PERCENT OF NORMAL...THE LOWEST SINCE SNOTELS WERE
INSTALLED IN THE EARLY 1980S. SNOWPACK IN EASTERN NEVADA IS HIGHER
THAN WESTERN NEVADA...BUT STILL BELOW NORMAL. THE SNOWPACK ACROSS
NORTHERN NEVADA IS ALSO BELOW NORMAL...BUT IN MUCH BETTER SHAPE THAN
FAR EASTERN NEVADA OR WESTERN NEVADA. THE HIGHEST SNOWPACK AS OF
FEBRUARY 1ST WAS IN THE SNAKE RIVER BASIN AT 97 PERCENT. THE LOWEST
FOR AREAS THAT REPORTED WAS THE LAKE TAHOE BASIN AT 17 PERCENT OF
AVERAGE.

SOME AREAS SAW HUGE DECLINES IN SNOW PACK FROM JANUARY 1ST TO
FEBRUARY 1ST. THE LARGEST OF THESE WAS IN THE CLOVER AND FRANKLIN
RIVER BASIN AT 55 PERCENT...THE NORTHERN GREAT BASIN AT 50 PERCENT
AND THE UPPER HUMBOLDT BASIN AT 43 PERCENT. MOST OTHER BASINS
DECLINED 20 TO 40 PERCENT.

                                 FEB 1 2015
BASIN               PERCENT OF AVERAGE
LAKE TAHOE ........................  17
TRUCKEE RIVER .....................  29
CARSON RIVER ......................  31
WALKER RIVER ......................  31
NORTHERN GREAT ....................  50
UPPER HUMBOLDT RIVER ..............  73
LOWER HUMBOLDT RIVER ..............  42
CLOVER VALLEY & FRANKLIN RIVER ....  91
SNAKE RIVER .......................  97
OWYHEE RIVER ......................  84
EASTERN NEVADA ....................  68
LOWER COLORADO RIVER ..............  NA

3/PRECIPITATION...
THE FIRST THREE MONTHS OF THE WATER YEAR RESULTED IN BELOW AVERAGE
PRECIPITATION FOR FAR WESTERN NEVADA AND EASTERN CALIFORNIA AND
JANUARY WAS EXCEPTIONALLY DRY...ADDING TO THIS DEFICIT.

FOR THE MONTH OF JANUARY ONLY EASTERN NEVADA RECORDED MORE THAN HALF
OF ITS NORMAL PRECIPITATION. THE REMAINDER OF THE NORTHEAST AND
NORTH CENTRAL NEVADA BASINS RECEIVED FROM 30 TO 50 PERCENT OF THEIR
AVERAGES. IN THE EASTERN SIERRA WATERSHEDS...20 OUT 24 SNOTEL SITES
RECORDED THEIR DRIEST JANUARY SINCE THEIR INSTALLATION...AND THE
REMAINING FOUR RECORDED THEIR SECOND DRIEST JANUARY.

SINCE THE START OF THE WATER YEAR IN OCTOBER...WESTERN NEVADA AND
THE EASTERN SIERRA HAVE RECEIVED LESS THAN 50 PERCENT OF THEIR
AVERAGE PRECIPITATION...EXCEPT FOR THE NORTHERN GREAT BASIN WHICH
STOOD AT 96 PERCENT OF AVERAGE. EASTERN NEVADA HAS FARED A LITTLE
BETTER THAN THE WESTERN BASINS AT 65 PERCENT. THE NORTH CENTRAL AND
NORTHEAST BASINS WERE ALL AT 80 PERCENT OR BETTER AS OF THE START OF
FEBRUARY...BUT NO BASINS WERE ABOVE AVERAGE.

                                WATER YEAR 2015
                              /THROUGH 2/6/2015/
BASIN                         PERCENT OF AVERAGE
LAKE TAHOE .........................  43
TRUCKEE RIVER ......................  50
CARSON RIVER .......................  40
WALKER RIVER .......................  39
NORTHERN GREAT .....................  96
UPPER HUMBOLDT RIVER ...............  81
LOWER HUMBOLDT RIVER ...............  85
CLOVER VALLEY AND FRANKLIN RIVER ...  94
SNAKE RIVER ........................  90
OWYHEE RIVER .......................  93
EASTERN NEVADA .....................  65
LOWER COLORADO RIVER ...............  NA

4/RESERVOIRS...
STORAGE IN MOST RESERVOIRS IN NEVADA AND EASTERN CALIFORNIA REMAIN
WELL BELOW AVERAGE. IN EARLY FEBRUARY RESERVOIR STORAGE IN NORTHERN
NEVADA AND EASTERN CALIFORNIA VARIED FROM A HIGH OF 39 PERCENT OF
AVERAGE ON THE TRUCKEE RIVER BASIN TO A LOW OF 0 PERCENT OF AVERAGE
IN THE LAKE TAHOE BASIN. THIS 0 PERCENT AT LAKE TAHOE IS DUE TO THE
LAKE`S FALLING BELOW ITS NATURAL RIM IN LATE FALL. THE LEVEL OF LAKE
TAHOE AT THE START OF FEBRUARY WAS 6222.42 FEET...WHICH EQUATES TO A
STORAGE DEFICIT OF 70,300 ACRE-FEET AS NO WATER CAN FLOW OUT OF THE
LAKE BELOW ITS NATURAL RIM OF 6223.0 FEET. IN SOUTHERN NEVADA THE
LOWER COLORADO BASIN HAD A STORAGE OF 56 PERCENT OF AVERAGE.

BASIN                        PERCENT OF CAPACITY   PERCENT OF AVERAGE
LAKE TAHOE ........................   0 ................   0
TRUCKEE RIVER .....................  23 ................  39
CARSON RIVER ......................   8 ................  16
WALKER RIVER ......................  10 ................  21
LOWER HUMBOLDT RIVER ..............   5 ................  11
OWYHEE RIVER ......................  17 ................  37
LOWER COLORADO RIVER ..............  44 ................  56

5/STREAMFLOW...
APRIL THROUGH JULY STREAMFLOW FORECASTS FOR MUCH OF NEVADA AND
EASTERN CALIFORNIA AS OF FEBRUARY 1ST ARE FORECAST TO BE BELOW TO
WELL BELOW AVERAGE. FOR PARTS OF NORTHEAST NEVADA STREAMFLOW
FORECASTS ARE EXPECTED TO BE SLIGHTLY BELOW AVERAGE IF A TYPICAL
PRECIPITATION PATTERN IS EXPERIENCED THROUGH THE REMAINDER OF THE
WINTER AND EARLY SPRING. FOR SOUTHERN NEVADA STREAMFLOWS ON THE
VIRGIN RIVER ARE EXPECTED TO BE WELL BELOW AVERAGE. ALL LOCATIONS
SAW SIGNIFICANT DROPS IN STREAMFLOW FORECASTS FROM JANUARY 1ST TO
FEBRUARY 1ST DUE TO THE VERY DRY JANUARY.

FEBRUARY 1ST STREAMFLOW FORECASTS WERE HIGHEST ON THE SNAKE RIVER AT
85 PERCENT OF AVERAGE AND LOWEST ON THE CARSON RIVER AT CARSON CITY
AT 20 PERCENT OF AVERAGE. THE VIRGIN RIVER AT LITTLEFIELD IN THE
LOWER COLORADO BASIN IS FORECAST TO BE 29 PERCENT OF AVERAGE.

                    PERCENT OF AVERAGE APRIL TO JULY STREAMFLOW
                 MOST PROBABLE FORECAST FROM NRCS AS OF FEB 1 2015
BASIN                    (50 PERCENT CHANCE OF EXCEEDANCE)
LAKE TAHOE RISE ...................... 34 .. 0.5 FOOT RISE
TRUCKEE RIVER ........................ 41 .. FARAD
CARSON RIVER ......................... 20 .. CARSON CITY
WEST WALKER RIVER .................... 42
EAST WALKER RIVER .................... 24
NORTHERN GREAT ....................... 32 .. MCDERMITT
UPPER HUMBOLDT RIVER ................. 49 .. PALISADE
LOWER HUMBOLDT RIVER ................. 22 .. IMLAY
CLOVER VALLEY AND FRANKLIN RIVER ..... 58
SNAKE RIVER .......................... 85
OWYHEE RIVER ......................... 50
EASTERN NEVADA ....................... 30 .. ELY
LOWER COLORADO RIVER ................. 29 .. LITTLEFIELD

6/ DROUGHT STATUS...
AS OF FEBRUARY 3 2015...THE UNITED STATES DROUGHT MONITOR CLASSIFIED
MUCH OF WESTERN NEVADA...INCLUDING CHURCHILL...PERSHING...STOREY...
CARSON CITY...DOUGLAS...MINERAL...WESTERN LANDER AND SOUTHERN WASHOE
COUNTIES IN NEVADA AS IN EXCEPTIONAL DROUGHT /LEVEL 4 OF 4 LEVELS OF
DROUGHT/. IN CALIFORNIA...MUCH OF LASSEN...PARTS OF PLUMAS...
SIERRA...NEVADA...PLACER...EL DORADO COUNTIES...ALL OF ALPINE COUNTY
AND MUCH OF MONO COUNTY WERE CLASSIFIED IN EXCEPTIONAL DROUGHT. THE
REMAINDER OF EASTERN CALIFORNIA AND WESTERN NEVADA WAS CLASSIFIED AS
IN EXTREME DROUGHT /LEVEL 3 OF 4 LEVELS OF DROUGHT/. IN EASTERN AND
SOUTHERN NEVADA...PARTS OF ELKO...EUREKA AND NYE COUNTIES WERE
CLASSIFIED AS HAVING EXTREME DROUGHT WHILE THE REMAINDER OF EASTERN
AND SOUTHERN NEVADA WAS CLASSIFIED AS BEING EITHER ABNORMALLY DRY OR
HAVING MODERATE TO SEVERE DROUGHT. MUCH OF INYO COUNTY IN CALIFORNIA
WAS CLASSIFIED AS HAVING EXTREME DROUGHT. FAR SOUTHEAST INYO COUNTY
AND MUCH OF SAN BERNARDINO COUNTY WERE ALSO NOTED AS BEING
ABNORMALLY DRY OR HAVING MODERATE TO SEVERE DROUGHT.

POSSIBLE IMPACTS FROM DROUGHT IN NEVADA AND EASTERN CALIFORNIA
INCLUDE...

HIGH FIRE DANGER THIS COMING SUMMER...AS TEMPERATURES WARM AND FUELS
DRY.

POSSIBLE WATER SUPPLY DEFICITS...RESERVOIR STORAGE REMAINS LOW AND
WATER SUPPLY COULD BECOME AN ISSUE THROUGHOUT THE REGION THIS SPRING
AND SUMMER IF SIGNIFICANT PRECIPITATION DOES NOT OCCUR OVER THE NEXT
FEW WEEKS. WATER SUPPLY CONCERNS WOULD BE HIGHEST ON BASINS WITHOUT
RESERVOIR STORAGE.

7/ LONG RANGE WEATHER OUTLOOK FOR NEVADA AND EASTERN CALIFORNIA. THE
OUTLOOK FOR LATE FEBRUARY IS FOR ABOVE NORMAL TEMPERATURES. THE
ENTIRE REGION HAS EQUAL CHANCES OF ABOVE...NEAR AND BELOW NORMAL
PRECIPITATION.

THE OUTLOOK FOR THE MONTHS OF MARCH THROUGH MAY IS FOR ABOVE NORMAL
PRECIPITATION ACROSS THE SOUTHERN 2/3RDS OF NEVADA AND EASTERN
CALIFORNIA FROM HIGHWAY 50 SOUTH. THE REMAINDER OF THE REGION IS
FORECAST TO HAVE EQUAL CHANCES OF NEAR...ABOVE AND BELOW NORMAL
PRECIPITATION. TEMPERATURES DURING THIS PERIOD ARE EXPECTED TO BE
ABOVE NORMAL FOR THE ENTIRE REGION.

8/ FOR MORE DETAILED WATER SUPPLY AND STREAMFLOW FORECAST
INFORMATION FOR NEVADA AND EASTERN CALIFORNIA...PLEASE REFER TO THE
FOLLOWING WEB SITES /NOTE...ALL LETTERS IN WEB SITE ADDRESSES ARE
LOWER CASE/...

NWS CALIFORNIA NEVADA RIVER FORECAST CENTER...
HTTP://WWW.CNRFC.NOAA.GOV/WATER_SUPPLY.PHP

NEVADA NATURAL RESOURCES CONSERVATION SERVICE...
HTTP://WWW.NV.NRCS.USDA.GOV/SNOW/

CALIFORNIA DEPT. OF WATER RESOURCES...
HTTP://CDEC.WATER.CA.GOV/

NWS CLIMATE PREDICTION CENTER LONG RANGE OUTLOOK MAPS...
HTTP://WWW.CPC.NCEP.NOAA.GOV/PRODUCTS/FORECASTS/

U.S. DROUGHT PORTAL...INCLUDING U.S. DROUGHT MONITOR...
HTTP://DROUGHT.GOV/

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