Flood Potential Outlook
Issued by NWS Pocatello, ID

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HYDROLOGIC OUTLOOK
NATIONAL WEATHER SERVICE POCATELLO ID
259 PM MST THU MAR 6 2014

...IDAHO SPRING FLOOD AND WATER SUPPLY OUTLOOK AS OF MARCH 2014...

...SPRING FLOOD RISK IS AVERAGE TO BELOW AVERAGE FOR IDAHO...

...NORMAL TO ABOVE NORMAL RUNOFF VOLUMES EXPECTED ACROSS EASTERN...
CENTRAL...AND NORTHERN IDAHO...

...BELOW NORMAL RUNOFF VOLUMES EXPECTED ACROSS SOUTH CENTRAL AND
SOUTHWEST IDAHO...

AT THIS TIME...THE RISK OF SIGNIFICANT SPRING FLOODING DUE TO
SNOWMELT IS AVERAGE ACROSS NORTHERN AND CENTRAL IDAHO...AS WELL AS
THE UPPER SNAKE RIVER AND BEAR RIVER REGION. FOR THE REMAINDER OF
THE STATE...THE RISK OF SIGNIFICANT SPRING FLOODING DUE TO SNOWMELT
IS BELOW AVERAGE. ONE THING TO REMEMBER IS THAT MOUNTAIN SNOWPACK
ACROSS IDAHO TYPICALLY PEAKS IN EARLY APRIL...LEAVING SEVERAL WEEKS
TO POTENTIALLY BOOST OUR SNOWPACK AND CHANGE THE FLOOD POTENTIAL.

RESERVOIR SYSTEMS ACROSS THE STATE ARE GENERALLY HOLDING AVERAGE OR
BELOW AVERAGE VOLUMES OF WATER. BASED ON THE CURRENT SNOWPACK AND
LONG TERM WEATHER OUTLOOKS THERE WILL BE ADEQUATE RESERVOIR SPACE TO
ACCOMMODATE THE SPRING RUNOFF.

THE PRIMARY FACTORS IN THE DEVELOPMENT OF SIGNIFICANT SPRING RIVER
FLOODING ARE THE OCCURRENCE OF PERSISTENT ABOVE NORMAL TEMPERATURES
...AND RAIN ON SNOW PRECIPITATION EVENTS. EVEN FOR AREAS WHERE
DROUGHT CONDITIONS EXIST...OR THAT HAVE LOW SNOWPACK...SPRING
FLOODING IS POSSIBLE UNDER THE RIGHT SCENARIO. ADDITIONALLY...BURN
SCARS CAN HAVE A SIGNIFICANT IMPACT ON LOCAL FLOOD POTENTIAL DURING
SPRING SNOWMELT.

IT IS NOT ALWAYS POSSIBLE TO FORECAST SPECIFIC RAIN STORMS...RAIN
ON SNOW EVENTS...OR EXTREME TEMPERATURE EVENTS MORE THAN 4 TO 7
DAYS INTO THE FUTURE. THEREFORE...SHORT RANGE RIVER FORECASTS
SHOULD BE MONITORED CLOSELY. DETAILS REGARDING POSSIBLE OR
RESULTING FLOODING WILL BE AVAILABLE IN SHORT TERM OUTLOOKS...FLOOD
WATCHES AND FLOOD WARNINGS ISSUED BY THE NATIONAL WEATHER SERVICE.

THE NATIONAL WEATHER SERVICE WATER SUPPLY OUTLOOK FOR IDAHO FOR THE
2014 WATER YEAR PROJECTS NEAR AVERAGE TO ABOVE AVERAGE RUNOFF
VOLUMES FOR THE PANHANDLE REGION...SOUTH ACROSS THE CLEARWATER AND
SALMON RIVER AREAS AND MUCH OF THE CENTRAL MOUNTAINS...AS WELL AS
THE UPPER SNAKE RIVER AND BEAR RIVER REGIONS. ELSEWHERE...THE
OUTLOOK IS NOT AS PROMISING...WITH BELOW AVERAGE RUNOFF VOLUMES
EXPECTED. SOUTH SIDE SNAKE RIVER BASINS NEAR THE NEVADA BORDER AND
THE MAGIC VALLEY AREA ARE THE DRIEST IN THE STATE...WITH FORECASTS
INDICATING AROUND 60 PERCENT OR LESS OF NORMAL RUNOFF.

SUMMARY OF 2014 WATER YEAR...

THE 2014 WATER YEAR STARTED OFF VERY DRY ACROSS IDAHO. JANUARY
MARKED THE FOURTH CONSECUTIVE MONTH THAT BELOW NORMAL PRECIPITATION
OCCURRED ACROSS ALMOST THE ENTIRE STATE. AT THE END OF JANUARY...
WITH EXCEPTION OF THE CLEARWATER BASIN AND EXTREME SOUTHEAST IDAHO
...WATER YEAR PRECIPITATION WAS LESS THAN LESS THAN 75 PERCENT OF
NORMAL ACROSS IDAHO...AND MUCH OF SOUTH CENTRAL AND SOUTHWEST IDAHO
HAD ONLY RECEIVED ABOUT 50 PERCENT OF NORMAL. BY THE BEGINNING OF
FEBRUARY...THE WEATHER PATTERN RESPONSIBLE FOR THE PERSISTENT
DRYNESS FINALLY GAVE WAY TO A BENEFICIAL WESTERLY FLOW OFF THE
PACIFIC OCEAN. THE RESULT WAS A VERY WET FEBRUARY WHERE MOST OF THE
STATE RECEIVED OVER 130 PERCENT OF NORMAL PRECIPITATION...AND MUCH
OF THE MOUNTAINS RECEIVED 200 TO 300 PERCENT OF NORMAL. THIS GAVE A
SIGNIFICANT BOOST TO MOUNTAIN SNOWPACK AND GREATLY IMPROVED
RESERVOIR STORAGE IN MOST AREAS. THE WET WEATHER HAS CONTINUED INTO
MARCH WITH MOST OF IDAHO HAVING RECEIVED 150 PERCENT OR MORE THAN
NORMAL PRECIPITATION THROUGH THE FIRST WEEK OF THE MONTH.

ALTHOUGH FEBRUARY AND EARLY MARCH HAVE BROUGHT ABUNDANT
PRECIPITATION AND PROVIDED A MUCH IMPROVED WATER SUPPLY OUTLOOK...
MUCH OF SOUTH CENTRAL AND SOUTHWEST IDAHO STILL SUFFER FROM
PROLONGED DROUGHT AND ARE FACING WATER SUPPLY SHORTAGES DURING THE
GROWING SEASON.

REFER TO SECTIONS BELOW AND LINKS PROVIDED FOR THE LATEST DETAILS
REGARDING WATER SUPPLY FORECASTS FOR SPECIFIC LOCATIONS...SNOWPACK
...PRECIPITATION...RESERVOIR CONDITIONS AND LONG TERM WEATHER
OUTLOOKS.

WATER SUPPLY VOLUME FORECASTS...

WATER SUPPLY FORECASTS ISSUED BY THE NORTHWEST AND COLORADO BASIN
RIVER FORECAST CENTERS ARE ISSUED FREQUENTLY...ON EITHER A WEEKLY
OR DAILY BASIS. FOR THE LATEST WATER SUPPLY FORECASTS FOR IDAHO
PLEASE REFER TO THE FOLLOWING WEB SITES.

NATIONAL WEATHER SERVICE-NORTHWEST RIVER FORECAST CENTER
WWW.NWRFC.NOAA.GOV/WS/

NATIONAL WEATHER SERVICE-COLORADO BASIN RIVER FORECAST CENTER
(BEAR RIVER BASIN)
HTTP://WWW.CBRFC.NOAA.GOV/

USDA-NATURAL RESOURCES CONSERVATION SERVICE
HTTP://WWW.NRCS.USDA.GOV/WPS/PORTAL/NRCS/MAIN/ID/SNOW/

SNOWPACK INFORMATION...

AS OF MARCH 6...BASIN SNOWPACK VARIED CONSIDERABLY ACROSS IDAHO.
THE LOWEST PERCENTAGES WERE ACROSS SOUTHWEST AND SOUTH CENTRAL
IDAHO...WITH THE OWYHEE BASIN THE LOWEST AT ONLY 52 PERCENT OF
NORMAL. MEANWHILE...MOST OF EASTERN IDAHO...AND THE CENTRAL
MOUNTAINS...NORTH ACROSS THE PANHANDLE REGION WERE ALL HOLDING
NEAR NORMAL OR ABOVE NORMAL SNOWPACK. THE UPPER SNAKE BASIN ABOVE
PALISADES HAD THE HIGHEST PERCENTAGE OF NORMAL AT 146 PERCENT.

CURRENT DAY SNOW WATER EQUIVALENT AND PERCENT OF NORMAL SNOWPACK
INFORMATION CAN BE FOUND AT THE FOLLOWING LINKS.

NATIONAL WEATHER SERVICE-NORTHWEST RIVER FORECAST CENTER
WWW.NWRFC.NOAA.GOV/SNOW/

NATIONAL WEATHER SERVICE-NATIONAL OPERATIONAL HYDROLOGIC REMOTE
SENSING CENTER
HTTP://WWW.NOHRSC.NOAA.GOV/

USDA-NATURAL RESOURCES CONSERVATION SERVICE
WWW.ID.NRCS.USDA.GOV/SNOW/DATA/CURRENT.HTML

RESERVOIR STORAGE

BUREAU OF RECLAMATION RESERVOIR STORAGE
WWW.USBR.GOV/PN/HYDROMET/SELECT.HTML

USDA-NATURAL RESOURCES CONSERVATION SERVICE
WWW.WCC.NRCS.USDA.GOV/CGIBIN/RESV-GRAPH.PL?STATE=ID

DROUGHT CONDITIONS

ACCORDING TO THE U.S. DROUGHT MONITOR...AS OF MARCH 4...MODERATE TO
EXTREME DROUGHT CONDITIONS EXIST ACROSS MOST OF SOUTH CENTRAL AND
SOUTHWEST IDAHO.  PROLONGED DROUGHT CONDITIONS LAST YEAR...AND
THROUGH THE FIRST SEVERAL MONTHS OF THE CURRENT WATER YEAR...HAVE
LEFT LONG TERM IMPACTS ON RESERVOIR STORAGE AND WATER SUPPLY IN
SOUTH CENTRAL AND SOUTHWEST IDAHO. THE 90 DAY U.S. SEASONAL DROUGHT
OUTLOOK INDICATES A POSSIBLE REMOVAL OR RELAXATION OF THE DROUGHT
INTENSITY IN ALL OF EASTERN IDAHO AND THE CENTRAL MOUNTAINS.

FOR THE LATEST DROUGHT CONDITIONS ACROSS THE REGION PLEASE REFER TO
THE FOLLOWING WEB SITES.

U.S. DROUGHT PORTAL
HTTP://WWW.DROUGHT.GOV

U.S. DROUGHT MONITOR
HTTP://WWW.DROUGHTMONITOR.UNL.EDU/

NATIONAL DROUGHT MITIGATION CENTER
HTTP://DROUGHT.UNL.EDU/

PEAK FLOW FORECASTS...

FOR PEAK FLOW FORECASTS PLEASE REFER TO THE FOLLOWING WEB SITES.

NORTHWEST RIVER FORECAST CENTER PEAK FLOW
HTTP://WWW.NWRFC.NOAA.GOV/PEAK/

COLORADO BASIN RIVER FORECAST CENTER PEAK FLOW
HTTP://WWW.CBRFC.NOAA.GOV/RMAP/PEAK/PEAKLIST.PHP

TEMPERATURE AND PRECIPITATION OUTLOOK...

ACCORDING TO THE CLIMATE PREDICTION CENTER...THE LONG RANGE OUTLOOK
FOR MARCH THROUGH MAY FAVORS ABOVE NORMAL TEMPERATURES ACROSS
SOUTHEAST AND SOUTHWEST IDAHO...AND EQUAL CHANCES OF BELOW AVERAGE...
AVERAGE OR ABOVE AVERAGE TEMPERATURES ACROSS NORTHEAST AND
NORTHERN IDAHO. FOR PRECIPITATION DURING THE MARCH THROUGH MAY
PERIOD...THERE ARE EQUAL CHANCES OF BELOW AVERAGE...AVERAGE...OR
ABOVE AVERAGE PRECIPITATION ACROSS THE STATE.

THE NATIONAL WEATHER SERVICE CLIMATE PREDICTION CENTER HAS ISSUED AN
EL NINO WATCH...INDICATING ABOUT A 50 PERCENT CHANCE OF EL NINO
DEVELOPING DURING THE SUMMER OR FALL OF 2014. TYPICAL WINTER TIME
IMPACTS OF EL NINO ON IDAHO WEATHER ARE FOR WARMER THAN NORMAL
TEMPERATURES.

FOR EL NINO INFORMATION AND LONG RANGE AND SEASONAL OUTLOOKS ISSUED
BY THE NATIONAL WEATHER SERVICE CLIMATE PREDICTION CENTER PLEASE
REFER TO THE FOLLOWING WEBSITE.
WWW.CPC.NCEP.NOAA.GOV/

$$







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