Water Supply Outlook: NWS Salt Lake City, UT

EXTENDED STREAMFLOW FORECAST
NATIONAL WEATHER SERVICE SALT LAKE CITY UTAH
230 PM MDT FRI FEB 4 2005

               EXTENDED STREAMFLOW FORECAST
                           UTAH

SUMMARY

WATER SUPPLY CONDITIONS ARE IMPROVING STATEWIDE. THE IMPROVEMENT IN 
SOUTHERN UTAH IS QUITE DRAMATIC BUT TO A FAR LESSER EXTENT IN THE 
NORTH. SOUTHERN UTAH AND THE UINTAH BASINS SNOWPACKS ARE ON A RECORD 
PACE.  MANY SITES ARE ABOVE 200 PERCENT OF AVERAGE WITH SOME PUSHING 
400 PERCENT.

THE UINTAH BASIN...THE SEVIER...SOUTHWEST UTAH AND THE ESCALANTE ARE 
ALL ABOVE THEIR AVERAGE APRIL 1 SNOWPACK WITH 2 MONTHS OF 
ACCUMULATION REMAINING. THE SEVIER AND SOUTHWEST UTAH HAVE SET NEW 
RECORD HIGH FEBRUARY 1 SNOWPACKS AND THE UINTAH BASIN HAS TIED THE 
RECORD.  THE POTENTIAL FOR NEW RECORD MAXIMUM SNOWPACKS IN 
THESE AREAS IS SUBSTANTIAL.  WITH RECORD SNOWPACKS...COMES THE 
POTENTIAL FOR VERY HIGH SNOWMELT STREAMFLOW.  FOR SOME STREAMS LIKE 
COAL CREEK WHICH HAS OVER 350 PERCENT OF AVERAGE SNOWPACK AND IS 
JUST AN INCH SHY OF THE RECORD MAXIMUM SNOWPACK ALREADY...IT IS NOT 
IF...BUT MERELY WHEN...THE HIGH FLOWS WILL OCCUR.  WHILE MANY 
OUTCOMES REMAIN POSSIBLE IN THESE AREAS...IT IS PRUDENT TO BEGIN 
PREPARATION FOR POTENTIALLY HIGH SNOWMELT STREAMFLOW THIS SPRING.  
IN OTHER UTAH WATERSHEDS...SNOWPACKS ARE STILL ABOVE AVERAGE...BUT 
SOME ONLY MARGINALLY SO.

THE BEAR RIVER IS THE LOWEST AT 109 PERCENT WITH THE WEBER AT 127 
PERCENT AND THE PROVO AT 141 PERCENT.  GIVEN AVERAGE ACCUMULATION 
FOR FEBRUARY AND MARCH...NORTHERN UTAH WILL HAVE SNOWPACKS FROM 110 
TO 130 PERCENT OF AVERAGE. SOUTHERN UTAH AND THE UINTAH BASIN WILL 
HAVE BETWEEN 150 AND 200 PERCENT OF AVERAGE.

PRECIPITATION FOR JANUARY WAS MUCH ABOVE AVERAGE STATEWIDE AT 167 
PERCENT.  NORTHERN UTAH RANGED FROM 120 TO 150 PERCENT AND SOUTHERN 
UTAH HAD 200 TO 360 PERCENT OF AVERAGE.  THIS BRINGS THE SEASONAL 
PRECIPITATION... (OCT-JAN) TO 157 PERCENT.  SOIL MOISTURE WAS 
SUBSTANTIALLY RECHARGED FROM LARGE PRECIPITATION EVENTS IN THE LATE 
FALL AND EARLY WINTER AS WELL AS THE RECENT PRECIPITATION EVENTS. 
CURRENT SOIL MOISTURE ACROSS THE ENTIRE STATE IS ONLY ABOUT 10 TO 15 
PERCENT LESS THAN WHAT IT WAS DURING ACTIVE SNOWMELT OF LAST 
SPRING.  ESTIMATES OF SOIL MOISTURE RANGE FROM ABOUT 50 TO 75 PERCENT 
OF SATURATION IN THE UPPER 24 INCHES OF SOIL.

HOWEVER...LOW RESERVOIR STORAGE IS A CONCERN WITH TOTAL RESERVOIR 
STORAGE AT 42 PERCENT OF CAPACITY...UP 3 PERCENT FROM LAST YEAR.  
THE AREA OF GREATEST DROUGHT CONCERN IS THE BEAR RIVER WITH CURRENT 
RESERVOIR STORAGE AT ONLY 2 PERCENT OF CAPACITY.

AREAS THAT COULD HAVE HIGH STREAMFLOWS INCLUDE THE UINTAH 
BASIN...SOUTHEAST UTAH...ESCALANTE...UPPER SEVIER AND THE VIRGIN.  
STREAMFLOW FORECASTS RANGE FROM 60 TO 290 PERCENT OF AVERAGE.  
SURFACE WATER SUPPLY INDICES RANGE FROM 4 PERCENT ON THE BEAR 
RIVER...TO 95 PERCENT ON THE VIRGIN.

SNOWPACK

FEBRUARY FIRST SNOWPACKS AS MEASURED BY THE NRCS SNOTEL SYSTEM RANGE 
FROM 109 PERCENT ON THE BEAR TO 247 PERCENT ON SOUTHWESTERN UTAH.  
MOST AREAS IN NORTHERN UTAH ARE 15 TO 30 PERCENT HIGHER THAN LAST 
YEAR...WHEREAS THE UNTAH BASIN AND EVERYTHING SOUTH OF SALINA HAVE 
DOUBLE AND TRIPLE SNOWPACKS OF THE LAST YEAR. THE MIDWAY VALLEY 
SNOTEL SITE CURRENTLY HAS 49.1 INCHES OF SNOW WATER EQUIVALENT AND 
ITS APRIL 1 AVERAGE PEAK IS ONLY 27 INCHES. OF SOME CONCERN ARE LOW 
ELEVATION SNOWPACKS ACROSS THE STATE...WHICH ARE BELOW AVERAGE.  THE 
UINTAH BASIN...UPPER SEVIER AND SOUTHWEST UTAH HAVE ALREADY 
SURPASSED THEIR APRIL 1 SNOWPACK AVERAGE AND COULD EASILY BE IN THE 
150 TO 200 PERCENT OF AVERAGE CATEGORY BY APRIL 1.  ANY OUTCOME IS 
STILL POSSIBLE IN NORTHERN UTAH...INCLUDING CONTINUED DROUGHT 
CONDITIONS.

PRECIPITATION

MOUNTAIN PRECIPITATION DURING JANUARY WAS MUCH ABOVE AVERAGE OVER 
SOUTHERN UTAH AND THE UINTAH BASIN (200-300 PERCENT). IN NORTHERN 
UTAH...PRECIPITATION WAS 115 TO 150 PERCENT OF AVERAGE.  THIS BRINGS 
THE SEASONAL ACCUMULATION (OCT-JAN) TO 157 PERCENT OF AVERAGE 
STATEWIDE.

RESERVOIRS

STORAGE IN 41 OF UTAH'S KEY IRRIGATION RESERVOIRS IS AT 42 PERCENT 
OF CAPACITY. THIS IS AN INCREASE OF 3 PERCENT FROM LAST YEAR AND 
REFLECTS HEAVY USE OF RESERVOIR STORAGE TO MAKE UP THE STREAMFLOW 
DEFICIT DURING YEARS OF DROUGHT.  MOST RESERVOIR OPERATORS ARE 
UTILIZING A CONSERVATIVE STRATEGY...STORING AS MUCH WATER AS 
POSSIBLE.

STREAMFLOW

SNOWMELT STREAMFLOWS ARE EXPECTED TO BE BELOW AVERAGE TO WELL ABOVE 
AVERAGE ACROSS THE STATE OF UTAH THIS YEAR.  FORECAST STREAMFLOWS 
RANGE FROM 58 PERCENT ON THE BEAR AT STEWART DAM TO 290 PERCENT ON 
COAL CREEK NEAR CEDAR CITY.  MOST FLOWS ARE FORECAST TO BE IN THE 
100 TO 160 PERCENT RANGE.  OVERALL WATER SUPPLY CONDITIONS ARE 
IMPROVING.

BRIAN MCINERNEY                     RANDY JULANDER
HYDROLOGIST                         DATA COLLECTION SUPERVISOR
NATIONAL WEATHER SERVICE            NRCS