Flood Potential Outlook
Issued by NWS Reno, NV

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WATER SUPPLY OUTLOOK
NATIONAL WEATHER SERVICE RENO NV
135 PM PST FRI APR 5 2013

...WATER SUPPLY AND SPRING FLOOD POTENTIAL OUTLOOK FOR NEVADA AND
EASTERN CALIFORNIA AS OF APRIL 5 2013...

...WELL BELOW AVERAGE STREAMFLOW IS EXPECTED THIS SPRING AND SUMMER
REGION WIDE...

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

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

1/SUMMARY...WATER SUPPLY OUTLOOK...
STREAMFLOW IS EXPECTED TO BE WELL BELOW AVERAGE THIS SPRING AND
SUMMER REGION WIDE.

THE NORMAL WATER SUPPLY PRODUCTION SEASON FOR NEVADA AND EASTERN
CALIFORNIA...FROM ABOUT MID OCTOBER TO MID APRIL...BEGAN RELATIVELY
WET THIS YEAR. AS OF NEW YEARS DAY 2013 PRECIPITATION WAS WELL ABOVE
NORMAL THROUGHOUT THE SIERRA NEVADA AND NEAR NORMAL IN THE REMAINDER
OF EASTERN CALIFORNIA AND NEVADA. SNOWPACK AT THAT TIME WAS ALSO
WELL ABOVE NORMAL IN THE SIERRA NEVADA...NEAR NORMAL ON THE LOWER
HUMBOLDT RIVER DRAINAGE...BUT SNOWPACK IN THE REST OF NEVADA WAS
BELOW AVERAGE AT THAT TIME.

HOWEVER...A RECORD DRY JANUARY...FEBRUARY...AND MARCH...THREE PRIME
WATER SUPPLY PRODUCTION MONTHS...HAS LEFT THE ENTIRE REGION VERY
DRY...FOR THE SECOND YEAR IN A ROW. ALL WE CAN HOPE FOR IS A VERY
WET APRIL TO TRY TO RECOVER SOMEWHAT FROM THE SEVERE WATER SUPPLY
DEFICIT THE REGION IS NOW IN. HOWEVER...CLIMATOLOGICALLY...EVEN A
WET APRIL WOULD NOT PROVIDE MORE THAN ABOUT FIVE TO TEN PERCENT OF
THE ANNUAL TOTAL WATER SUPPLY FOR THE REGION. AS OF APRIL
5TH...THERE ARE NO INDICATIONS FROM WEATHER FORECAST MODELS THAT A
WET APRIL WILL MATERIALIZE.

WHILE RESERVOIR STORAGE IS CURRENTLY ADEQUATE FOR THE MOST POPULATED
AREAS OF NEVADA AND EASTERN CALIFORNIA...MEETING ALL WATER NEEDS
THIS SUMMER IS GOING TO BE DIFFICULT...ESPECIALLY IN AREAS WHICH
RELY ON AN IRRIGATED AGRICULTURE ECONOMY. MANY AREAS WILL FACE
SHORTAGES AND SOME DIFFICULT DECISIONS WILL NEED TO BE MADE
REGARDING IRRIGATING AGRICULTURAL AREAS. WATER USERS WILL NEED TO
WORK CLOSELY WITH THEIR SUPPLIERS TO DETERMINE THE EXTENT OF ANY
RESTRICTIONS THAT MAY APPLY THIS YEAR.  AREAS WITH POOR RESERVOIR
STORAGE OR AGRICULTURAL AREAS THAT GET THEIR WATER DIRECTLY FROM A
RIVER OR CREEK CAN EXPECT THESE FLOWS TO DECLINE EARLIER THAN NORMAL
THIS YEAR.

2/SUMMARY...SPRING FLOOD POTENTIAL OUTLOOK...
FLOOD POTENTIAL IN NEVADA AND EASTERN CALIFORNIA IS WELL BELOW
AVERAGE THIS SPRING.

SPRING FLOOD POTENTIAL DEPENDS ON SEVERAL FACTORS.  THESE INCLUDE
SNOWPACK...SOIL MOISTURE...RESERVOIR STORAGE...AS WELL AS AIR
TEMPERATURE AND RAINFALL DURING THE SNOWMELT PERIOD.

AS OF APRIL 5TH...SNOWPACK WAS WELL BELOW AVERAGE THROUGHOUT NEVADA
AND EASTERN CALIFORNIA.  PRECIPITATION HAS BEEN EXTREMELY LIGHT
THROUGHOUT THE REGION SINCE LATE DECEMBER.  THE THREE MONTHS OF
JANUARY THROUGH MARCH HAVE SEEN NEAR RECORD LOW PRECIPITATION VALUES
FOR MUCH OF THE NORTHERN PART OF THE REGION.  THE 2013 WATER YEAR
/SINCE OCTOBER 2012/ IS ALSO WELL BELOW AVERAGE IN MOST OF THE
REGION...THE ONLY EXCEPTIONS BEING SOUTHERN LASSEN AND NORTHERN MONO
COUNTIES CALIFORNIA AND CENTRAL WHITE PINE COUNTY NEVADA. SO...SOILS
HAVE DRIED THROUGHOUT THE REGION.  THERE IS AMPLE RESERVOIR STORAGE
THROUGHOUT NEVADA AND EASTERN CALIFORNIA.

AS SNOWPACK IS BELOW AVERAGE...FLOODING FROM SNOWMELT IS VERY
UNLIKELY.  CLIMATOLOGICALLY...THE SEASON FOR FLOOD PRODUCING WINTER
STORMS HAS ENDED IN MOST OF THE REGION...THE EXCEPTION BEING
NORTHEASTERN NEVADA. HOWEVER...IF IT IS WARM AND WET DURING THE MELT
SEASON...SPRING FLOODING COULD STILL OCCUR.

3/SNOWPACK...
APRIL 1 SNOWPACK CONDITIONS FOR NEVADA AND EASTERN CALIFORNIA WERE
WELL BELOW AVERAGE. THERE ARE NO BRIGHT SPOTS THIS YEAR. COMING ON
THE HEELS OF VERY DRY CONDITIONS LAST YEAR...THE LACK OF SNOW WILL
LEAD TO WATER SHORTAGES FOR PARTS OF THE REGION...ESPECIALLY THOSE
THAT RELY ECONOMICALLY ON IRRIGATED AGRICULTURE.  JANUARY TO MARCH
WERE VERY DRY AND HAVE RESULTED IN SOME AREAS HAVING LOWER SNOWPACK
NUMBERS THAN LAST YEAR. THE LOWER HUMBOLDT RIVER BASIN HAD THE
HIGHEST APRIL 1 VALUE AT 75 PERCENT OF AVERAGE...WHILE THE NORTHERN
GREAT BASIN WAS LOWEST WITH NO SNOWPACK REMAINING AT ANY SNOW SITES
REPORTING.

                               LAST YEAR            THIS YEAR
BASIN   PERCENT OF AVERAGE   PERCENT OF AVERAGE
LAKE TAHOE.....................  55 ................  52
TRUCKEE RIVER..................  59 ................  60
CARSON RIVER...................  42 ................  63
WALKER RIVER...................  37 ................  72
NORTHERN GREAT.................  48 ................   0
UPPER HUMBOLDT RIVER...........  42 ................  66
LOWER HUMBOLDT RIVER...........  46 ................  75
CLOVER VALLEY & FRANKLINRIVER .  40 ................  63
SNAKE RIVER....................  48 ................  71
OWYHEE RIVER...................  35 ................  49
EASTERN NEVADA.................  55 ................  50
LOWER COLORADO RIVER...........  36 ................   2

4/PRECIPITATION...
MARCH PRECIPITATION FOR NEVADA AND EASTERN CALIFORNIA WAS
GENERALLY HALF OR LESS OF AVERAGE STATEWIDE.  THE EXCEPTION WAS
SOUTHERN NEVADA WHICH RECEIVED AVERAGE AMOUNTS FOR THE MONTH. THIS
LACK OF MOISTURE CONTINUED THE DRY SPELL WHICH BEGAN IN JANUARY HAS
LED TO FURTHER DECLINES IN WATER YEAR TOTALS FOR THE STATE.  MARCH
PRECIPITATION WAS HIGHEST IN THE LOWER COLORADO RIVER BASIN AT 103
PERCENT OF AVERAGE AND LOWEST IN EASTERN NEVADA AT 26 PERCENT OF
AVERAGE.  WATER YEAR PRECIPITATION IS HIGHEST IN THE SNAKE RIVER
BASIN AT 91 PERCENT OF AVERAGE AND LOWEST IN THE LOWER COLORADO
RIVER BASIN AT 47 PERCENT OF AVERAGE.

                                 MARCH 2013         WATER YEAR 2013
BASIN                         PERCENT OF AVERAGE   PERCENT OF AVERAGE
LAKE TAHOE .........................  50 ................  84
TRUCKEE RIVER ......................  40 ................  77
CARSON RIVER .......................  50 ................  75
WALKER RIVER .......................  45 ................  76
NORTHERN GREAT .....................  34 ................  77
UPPER HUMBOLDT RIVER ...............  43 ................  81
LOWER HUMBOLDT RIVER ...............  40 ................  85
CLOVER VALLEY AND FRANKLIN RIVER ...  55 ................  65
SNAKE RIVER ........................  52 ................  91
OWYHEE RIVER .......................  41 ................  85
EASTERN NEVADA .....................  26 ................  76
LOWER COLORADO RIVER ............... 103 ................  47

5/RESERVOIRS...
RESERVOIR STORAGE IN NEVADA AND EASTERN CALIFORNIA DECLINED DURING
MARCH ON MANY BASINS. END OF MARCH RESERVOIR STORAGE WAS HIGHEST ON
THE TRUCKEE RIVER BASIN AT 106 PERCENT OF AVERAGE. THE LOWER
HUMBOLDT RIVER BASIN WAS LOWEST AT 11 PERCENT OF AVERAGE.

BASIN                        PERCENT OF CAPACITY  PERCENT OF AVERAGE
LAKE TAHOE ........................  49 ................  93
TRUCKEE RIVER .....................  67 ................ 106
CARSON RIVER ......................  42 ................  62
WALKER RIVER ......................  32 ................  49
LOWER HUMBOLDT RIVER ..............  23 ................  11
OWYHEE RIVER ......................  40 ................  73
LOWER COLORADO RIVER ..............  54 ................  68

6/STREAMFLOW...
STREAMFLOW FORECASTS FOR NEVADA AND EASTERN CALIFORNIA ARE EXPECTED
TO BE WELL BELOW AVERAGE.  STREAMFLOW FORECASTS ARE HIGHEST FOR THE
WALKER RIVER BASIN AT 55 TO 61 PERCENT OF AVERAGE...AND LOWEST IN
THE LOWER HUMBOLDT RIVER BASIN AT 8 TO 10 PERCENT OF AVERAGE.

                          PERCENT OF AVERAGE APRIL TO JULY STREAMFLOW
                                    MOST PROBABLE FORECAST
BASIN                        /50 PERCENT CHANCE OF EXCEEDANCE/
                                      NRCS   NWS
LAKE TAHOE INFLOW....................  35    35
TRUCKEE RIVER .......................  47    47
CARSON RIVER ........................  40    39
WALKER RIVER ........................  61    55
NORTHERN GREAT ......................  58    NA
UPPER HUMBOLDT RIVER ................  38    22
LOWER HUMBOLDT RIVER ................  10     8
CLOVER VALLEY AND FRANKLIN RIVER ....  58    NA
SNAKE RIVER .........................  64    55
OWYHEE RIVER ........................  20    33
EASTERN NEVADA ......................  31    NA
LOWER COLORADO RIVER ................  34    45

7/ DROUGHT STATUS...
AS OF APRIL 3 2013...ALL COUNTIES IN NEVADA AND ALL CALIFORNIA
COUNTIES ALONG THE NEVADA BORDER REMAINED DESIGNATED NATURAL DROUGHT
DISASTER AREAS...EITHER AS PRIMARY COUNTIES OR CONTIGUOUS
COUNTIES...BY THE U.S. DEPARTMENT OF AGRICULTURE.

PRIMARY DROUGHT DISASTER COUNTIES IN CALIFORNIA ALONG THE NEVADA
BORDER INCLUDED MODOC...LASSEN...MONO...INYO AND SAN BERNARDINO.

ALL NEVADA COUNTIES HAD BEEN DECLARED PRIMARY DROUGHT DISASTER
COUNTIES WITH THE EXCEPTION OF ELKO...EUREKA...AND LINCOLN COUNTIES.

AS OF APRIL 2 2013...THE UNITED STATES DROUGHT MONITOR CLASSIFIED
PORTIONS OF WEST CENTRAL AND NORTHEASTERN NEVADA AS IN EXTREME
DROUGHT /LEVEL 3 OF 4 LEVELS OF DROUGHT/. THIS AREA INCLUDED MUCH OF
PERSHING...ALL OF CHURCHILL...EASTERN LYON AND EXTREME NORTHERN
MINERAL COUNTIES...AS WELL AS SOUTHEAST ELKO COUNTY.  ALL OF THE
REST OF NEVADA WAS IN MODERATE TO SEVERE DROUGHT /LEVELS 1 AND
2/...WITH THE EXCEPTION OF MOST OF CLARK AND NORTHERN ELKO
COUNTIES...WHICH WERE CLASSIFIED AS ABNORMALLY DRY.  IN
CALIFORNIA...MODOC AND MUCH OF LASSEN...AS WELL AS MONO...INYO...AND
MOST OF SAN BERNARDINO COUNTIES...REMAINED IN MODERATE TO SEVERE
DROUGHT.

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

HIGH FIRE DANGER THIS SUMMER...
AS TEMPERATURES WARM AND FUELS DRY FIRE DANGER WILL INCREASE. FIRE
DANGER WILL BE EXPECIALLY HIGH IN TIMBERED AREAS WHERE FUELS HAVE
BEEN DRIER THAN NORMAL FOR TWO CONSECUTIVE YEARS. AS OF APRIL
3...MUCH OF NEVADA WAS REPORTING HIGH TO VERY HIGH FIRE DANGER. FIRE
DANGER WAS ALSO RANKED HIGH TO VERY HIGH IN MUCH OF SOUTHEAST
CALIFORNIA. FIRE DANGER WAS RANKED AS LOW TO MODERATE IN NORTHEAST
CALIFORNIA AND THE CENTRAL SIERRA.

POSSIBLE WATER SUPPLY DEFICITS...
AREAS WHICH RELY ON IRRIGATED AGRICULTURE FOR A SIGNIFICANT PORTION
OF THEIR ECONOMY ARE ESPECIALLY VULNERABLE TO WATER SUPPLY SHORTAGES
THIS YEAR. WATER SUPPLY CONCERNS ARE HIGHEST ON BASINS WITHOUT
ADEQUATE RESERVOIR STORAGE.  AREAS THAT GET WATER DIRECTLY FROM A
RIVER OR CREEK THAT DOES NOT HAVE STORAGE CAN EXPECT FLOWS TO
DECLINE EARLIER THAN NORMAL THIS YEAR. HOWEVER...NO SIGNIFICANT
WATER SUPPLY SHORTAGES ARE EXPECTED AT THIS TIME IN ANY OF THE MAJOR
POPULATION CENTERS IN NEVADA OR EASTERN CALIFORNIA.

NATURAL VEGETATION AND WILDLIFE MAY BE IMPACTED AS SURFACE WATER
SOURCES DRY UP DURING THE SUMMER.

8/ LONG RANGE WEATHER OUTLOOK FOR NEVADA AND EASTERN CALIFORNIA...

THE OUTLOOK FOR APRIL 11 TO 19...IS FOR ABOVE NORMAL TEMPERATURES...
AND BELOW NORMAL PRECIPITATION.

THE OUTLOOK FOR THE MONTH OF APRIL...IS FOR ABOVE NORMAL
TEMPERATURES... ESPECIALLY IN EASTERN NEVADA...ALTHOUGH TEMPERATURES
IN WESTERN NEVADA AND NORTHEAST CALIFORNIA ARE EXPECTED TO BE NEAR
NORMAL. THERE ARE EQUAL CHANCES OF HAVING ABOVE NORMAL...NEAR NORMAL
OR BELOW NORMAL PRECIPITATION IN APRIL THROUGHOUT THE REGION.

THE LONG RANGE OUTLOOK FOR THE MONTHS OF APRIL THROUGH JUNE IS FOR
NEAR NORMAL TEMPERATURES EXCEPT IN EASTERN NEVADA WHERE TEMPERATURES
ARE EXPECTED TO BE SLIGHTLY ABOVE NORMAL.  BELOW NORMAL
PRECIPITATION IS EXPECTED THROUGHOUT THE 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...
WWW.CNRFC.NOAA.GOV/WATER_SUPPLY.PHP

NWS NORTHWEST RIVER FORECAST CENTER...
WWW.NWRFC.NOAA.GOV/WS/

NWS COLORADO BASIN RIVER FORECAST CENTER...
WWW.CBRFC.NOAA.GOV/

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

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

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

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

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