Flood Potential Outlook
Issued by NWS Reno, NV

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NVZ001>041-CAZ070>073-CAZ519>527-120000-

WATER SUPPLY AND SPRING FLOOD OUTLOOK
NATIONAL WEATHER SERVICE RENO NV
330 PM PST THU MAR 5 2015

...WATER SUPPLY AND SPRING FLOOD OUTLOOK FOR NEVADA AND EASTERN
CALIFORNIA AS OF MARCH 5 2015...

...FLOOD POTENTIAL IN NEVADA AND EASTERN CALIFORNIA IS BELOW AVERAGE
THIS SPRING...

...WELL BELOW AVERAGE STREAM FLOW IS EXPECTED THIS SPRING AND
SUMMER...

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

1/SUMMARY...SPRING FLOOD POTENTIAL OUTLOOK...
THE SPRING FLOOD POTENTIAL IN ALL BASINS IN NEVADA AND THE
WATERSHEDS EAST OF THE SIERRA CREST IN EASTERN CALIFORNIA IS BELOW
AVERAGE.

SPRING FLOOD POTENTIAL DEPENDS ON SEVERAL FACTORS. THESE INCLUDE
SNOWPACK...SOIL MOISTURE AND RESERVOIR STORAGE...ALONG WITH AIR
TEMPERATURE AND RAINFALL DURING THE SNOW MELT PERIOD.

PRECIPITATION HAS BEEN BELOW TO WELL BELOW NORMAL FOR MUCH OF NEVADA
AND EASTERN CALIFORNIA SINCE OCTOBER 2014. THE ONLY AREAS THAT HAVE
SEEN ABOVE NORMAL PRECIPITATION IN THAT TIME ARE LOCATED ACROSS
NORTHEAST CALIFORNIA...FAR NORTHWEST NEVADA...SOUTHERN INYO COUNTY
AND NORTHERN AND FAR EASTERN SAN BERNARDINO COUNTY IN EASTERN
CALIFORNIA.

RAINS IN DECEMBER AND FEBRUARY BOOSTED SOIL MOISTURE AND INCREASED
RESERVOIR STORAGE SLIGHTLY ACROSS EASTERN CALIFORNIA AND WESTERN
NEVADA...BUT THE STORMS THAT BROUGHT THESE RAINS WERE VERY WARM AND
ADDED LITTLE TO THE OVERALL SNOWPACK...WHICH REMAINS WELL BELOW
AVERAGE FOR EARLY MARCH.

THE BEST SNOWPACK IS LOCATED IN FAR NORTHEAST NEVADA IN THE UPPER
HUMBOLDT...SNAKE RIVER AND CLOVER VALLEY BASINS. EVEN THOUGH
RESERVOIR STORAGE INCREASED IN EARLY FEBRUARY...MOST REMAIN WELL
BELOW AVERAGE.

SO...UNLESS THERE IS A DRASTIC CHANGE OVER THE NEXT FEW WEEKS...
SPRING FLOOD POTENTIAL IN NEVADA AND EASTERN CALIFORNIA WILL REMAIN
BELOW AVERAGE FOR THE FOURTH CONSECUTIVE YEAR. AS THE WET SEASON CAN
EXTEND INTO MID APRIL...AND EVEN LATER IN NORTHEASTERN NEVADA...
CHANGE IS STILL POSSIBLE...THOUGH IT IS NOT LIKELY AT THIS POINT.

2/SUMMARY...WATER SUPPLY OUTLOOK...
THROUGH EARLY MARCH...NORTHWEST NEVADA HAD REAPED THE BENEFITS OF
NEAR TO SLIGHTLY ABOVE AVERAGE PRECIPITATION SINCE THE START OF
OCTOBER. HOWEVER...MUCH OF THE EASTERN SIERRA NEVADA IN
CALIFORNIA...FAR WESTERN NEVADA AND THE LOWER ELEVATIONS OF EASTERN
NEVADA WERE MISSED BY THE PRECIPITATION THAT BOOSTED THE NORTHWEST
PART OF THE STATE. EVEN WITH INCREASED PRECIPITATION IN SOME PARTS
OF THE REGION...THE PRECEDING THREE AND A HALF YEARS HAVE LEFT
RAINFALL DEFICITS OVER MUCH OF THE AREA. IN SOME PARTS OF WESTERN
NEVADA AND THE SIERRA NEVADA MOUNTAINS OVER A YEAR OF PRECIPITATION
HAS BEEN MISSED IN THE LAST THREE AND A HALF 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 WAS 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.

A SERIES OF WET...WARM STORMS MOVED THROUGH EASTERN CALIFORNIA AND
WESTERN NEVADA IN THE FIRST HALF OF FEBRUARY. THESE STORMS BOOSTED
PRECIPITATION OVER THE REGION...BUT HIGH SNOW LEVELS ONCE AGAIN
LIMITED INCREASES TO THE SNOWPACK. THE WARM...WET NATURE OF THESE
STORMS DID PRODUCE RUN OFF AND INCREASED STORAGE ON AREA RESERVOIRS.
A COLDER STORM IN LATE FEBRUARY BROUGHT SNOW TO WESTERN NEVADA AND
THE SIERRA ALONG WITH SNOW AND RAIN TO SOUTHERN NEVADA...TEMPORARILY
INCREASING THE SNOWPACK. HOWEVER...THE BENEFITS OF THIS STORM
LARGELY BYPASSED EASTERN NEVADA.

ONE BRIGHT SPOT...THESE STORMS RESULTED IN AN INCREASE IN SOIL
MOISTURE ACROSS THE SIERRA AND WESTERN NEVADA. THE TRUCKEE RIVER
BASIN RECORDED ITS HIGHEST MARCH 1ST SOIL MOISTURE BASED ON TEN
YEARS OF DATA. SOIL MOISTURE IS NEAR OR ABOVE AVERAGE FOR ALL AREAS
EXCEPT EASTERN NEVADA.

AS OF EARLY MARCH...STREAMFLOW FORECASTS ARE EXPECTED TO BE 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 FOUR TO SIX WEEKS WILL BE CRITICAL FOR SNOWPACK INTO THE
EARLY SPRING...AND WHAT THE SPRING AND SUMMER STREAMFLOWS WILL
BE. JUST A FEW WET STORMS WITH LOW SNOW LEVELS WOULD RESULT IN
IMPROVED CONDITIONS.

3/SNOWPACK...
SNOWPACK AS OF MARCH 1ST IN THE SIERRA NEVADA REMAINED WELL BELOW
AVERAGE. LAKE TAHOE`S SNOWPACK SAT AT 23 PERCENT OF NORMAL. SNOWPACK
IN THE SIERRA IS VYING WITH 1991 AS THE LOWEST ON RECORD SINCE
SNOTEL SITES WERE INSTALLED IN THE EARLY 1980S. TWENTY-TWO MEASURING
SITES ARE AT THEIR LOWEST OR SECOND LOWEST READINGS FOR THEIR PERIOD
OF RECORD. THE SNOWPACK ACROSS NORTHERN AND EASTERN NEVADA IS ALSO
BELOW NORMAL. THE CLOVER VALLEY AND FRANKLIN RIVER BASIN REPORTED
THE BEST SNOWPACK AT 77 PERCENT OF NORMAL.

BASINS IN THE NORTHEAST AND FAR EASTERN PART OF THE NEVADA RECORDED
THE STEEPEST DECLINES WITH RESPECT TO AVERAGE THROUGH THE MONTH. THE
OWYHEE BASIN HAD THE STEEPEST DECLINE AT 36 PERCENT. EASTERN NEVADA
SAW A DECREASE OF 28 PERCENT WHILE THE UPPER HUMBOLDT FELL 24
PERCENT AND THE SNAKE BASIN FELL 23 PERCENT.

                                 MAR 1 2015
BASIN               PERCENT OF AVERAGE
LAKE TAHOE ........................  23
TRUCKEE RIVER .....................  28
CARSON RIVER ......................  36
WALKER RIVER ......................  39
NORTHERN GREAT ....................  34
UPPER HUMBOLDT RIVER ..............  24
LOWER HUMBOLDT RIVER ..............  29
CLOVER VALLEY & FRANKLIN RIVER ....  77
SNAKE RIVER .......................  74
OWYHEE RIVER ......................  47
EASTERN NEVADA ....................  40
LOWER COLORADO RIVER ..............  NA

4/PRECIPITATION...
HEAVY PRECIPITATION IN EARLY FEBRUARY BOOSTED AVERAGES ACROSS THE
WESTERN PART OF NEVADA AND THE EASTERN SIERRA OF CALIFORNIA...BUT
MUCH OF NORTHERN AND EASTERN NEVADA MISSED THE BULK OF THIS
PRECIPITATION AND THEIR BASIN AVERAGES FELL THROUGH THE MONTH.

THE WET FEBRUARY HAS PUSHED THE WATER YEAR PRECIPITATION...SINCE THE
START OF OCTOBER...IN WESTERN NEVADA AND THE EASTERN SIERRA TO ABOVE
50 PERCENT OF AVERAGE...BUT THE TOTALS STILL REMAIN WELL BELOW
NORMAL. THE AVERAGE FOR THE NORTHERN GREAT BASIN FELL DURING THE
MONTH OF FEBRUARY ALONG WITH ALL OF THE BASINS IN THE NORTH
CENTRAL...NORTHEAST AND EASTERN PARTS OF NEVADA. THE CLOVER VALLEY
AND FRANKLIN RIVER BASIN REMAINS THE HIGHEST AT 90 PERCENT OF
AVERAGE WHILE THE NORTHERN GREAT BASIN...SNAKE BASIN AND OWYHEE
BASIN ALL REMAINED GREATER THAN 80 PERCENT OF AVERAGE.

                                                  WATER YEAR 2015
                                    FEB 2015    /THROUGH 3/1/2015/
BASIN                              PCT OF AVE        PCT OF AVE
LAKE TAHOE .........................  105  ...........   60
TRUCKEE RIVER ......................   89  ...........   61
CARSON RIVER .......................   93  ...........   53
WALKER RIVER .......................   89  ...........   52
NORTHERN GREAT .....................   56  ...........   87
UPPER HUMBOLDT RIVER ...............   43  ...........   74
LOWER HUMBOLDT RIVER ...............   47  ...........   79
CLOVER VALLEY AND FRANKLIN RIVER ...   71  ...........   90
SNAKE RIVER ........................   54  ...........   83
OWYHEE RIVER .......................   49  ...........   86
EASTERN NEVADA .....................   27  ...........   57
LOWER COLORADO RIVER ...............   NA  ...........   NA

5/RESERVOIRS...
WHILE RUN OFF FROM EARLY FEBRUARY PRECIPITATION RESULTED IN INCREASES
IN STORAGE THROUGHOUT MOST OF NORTHERN NEVADA AND EASTERN
CALIFORNIA...STORAGE IN MOST RESERVOIRS REMAINED WELL BELOW AVERAGE.
IN EARLY MARCH RESERVOIR STORAGE IN NORTHERN NEVADA AND EASTERN
CALIFORNIA VARIED FROM A HIGH OF 49 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
ON MARCH 1ST WAS 6222.85 FEET...WHICH EQUATES TO A STORAGE DEFICIT
OF 18,190 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 .....................  29 ................  49
CARSON RIVER ......................  14 ................  25
WALKER RIVER ......................  16 ................  31
LOWER HUMBOLDT RIVER ..............   5 ................  13
OWYHEE RIVER ......................  19 ................  39
LOWER COLORADO RIVER ..............  44 ................  56

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

MARCH 1ST STREAMFLOW FORECASTS WERE HIGHEST ON THE SNAKE RIVER AT 66
PERCENT OF AVERAGE AND LOWEST IN EASTERN NEVADA AT 15 PERCENT OF
AVERAGE ON STEPTOE CREEK NEAR ELY. THE CARSON RIVER AT CARSON CITY
AND HUMBOLDT RIVER AT IMLAY ARE BOTH FORECAST TO BE 16 PERCENT OF
AVERAGE. THE VIRGIN RIVER AT LITTLEFIELD IN THE LOWER COLORADO BASIN
IS FORECAST TO BE 34 PERCENT OF AVERAGE.

BELOW ARE FORECASTS FOR SELECTED RIVER POINTS ACROSS NEVADA AND
EASTERN CALIFORNIA. SOME CONTAIN BOTH THE NRCS FORECAST AND NWS
FORECAST PROVIDED BY THE ENSEMBLE STREAMFLOW PREDICTION SYSTEM AT
THE CALIFORNIA-NEVADA RIVER FORECAST CENTER. THE FORECASTS MAY
DIFFER SLIGHTLY BASED ON FORECAST METHODOLOGY.

                      PERCENT OF AVERAGE APRIL TO JULY STREAMFLOW
                        MOST PROBABLE FORECAST AS OF MAR 1 2015
                          (50 PERCENT CHANCE OF EXCEEDANCE)
BASIN                                 NRCS    NWS
LAKE TAHOE RISE ...................... 31 ...  5  .. 0.4 FOOT RISE (NRCS)
TRUCKEE RIVER ........................ 37 ... 40  .. FARAD
CARSON RIVER ......................... 16 ... 19  .. CARSON CITY
WEST WALKER RIVER .................... 38 ... 44
EAST WALKER RIVER .................... 27 ... 25
NORTHERN GREAT ....................... 26 ... NA  .. MCDERMITT
UPPER HUMBOLDT RIVER ................. 36 ... 46  .. PALISADE
LOWER HUMBOLDT RIVER ................. 16 ... 24  .. IMLAY
CLOVER VALLEY AND FRANKLIN RIVER ..... 38 ... NA
SNAKE RIVER .......................... 66 ... 61@
OWYHEE RIVER ......................... 27 ... 33@
EASTERN NEVADA ....................... 15 ... NA  .. ELY
LOWER COLORADO RIVER ................. 34 ... 29* .. LITTLEFIELD
SUSAN RIVER........................... NA ... 21  .. SUSANVILLE
MIDDLE FORK FEATHER RIVER............. NA ...  1  .. PORTOLA

NA - FORECAST EITHER NOT PROVIDED OR NOT PRODUCED FOR THIS LOCATION
*  - VIRGIN RIVER NWS FORECAST PROVIDED BY CBRFC IN SALT LAKE CITY
@  - SNAKE AND OWYHEE RIVER NWS FORECASTS PRODUCED BY NWRFC IN
     PORTLAND

7/ DROUGHT STATUS...
AS OF MARCH 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 AND
MONO COUNTIES AND A SMALL PART OF NORTHERN INYO COUNTY WERE
CLASSIFIED IN EXCEPTIONAL DROUGHT. MUCH OF 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 HAVING MODERATE TO SEVERE DROUGHT. FAR SOUTHEAST
INYO COUNTY AND MUCH OF SAN BERNARDINO COUNTY WERE ALSO NOTED AS
HAVING MODERATE TO SEVERE DROUGHT...EXCEPT AREAS ALONG THE COLORADO
RIVER WHICH WERE CLASSIFIED AS ABNORMALLY DRY.

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.

8/ LONG RANGE WEATHER OUTLOOK FOR NEVADA AND EASTERN CALIFORNIA. THE
OUTLOOK FOR MARCH IS FOR ABOVE NORMAL TEMPERATURES. NORTHEAST
CALIFORNIA AND FAR NORTHWEST NEVADA ARE EXPECTED TO HAVE BELOW
NORMAL PRECIPITATION. THE REMAINDER OF THE REGION HAS EQUAL CHANCES
OF ABOVE...NEAR AND BELOW NORMAL PRECIPITATION.

THE OUTLOOK FOR THE MONTHS OF APRIL THROUGH JUNE IS FOR ABOVE NORMAL
PRECIPITATION OVER FAR SOUTHEAST NEVADA AND SOUTHEAST CALIFORNIA
NEAR THE COLORADO RIVER. 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.

9/ 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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