HYDROLOGIC OUTLOOK NATIONAL WEATHER SERVICE BOISE IDAHO 920 AM MDT WED FEB 9 2005
...IDAHO SPRING FLOOD OUTLOOK AND WATER SUPPLY FORECAST...
DISCUSSION...
BELOW NORMAL PRECIPITATION AND ABOVE NORMAL TEMPERATURES HAVE BEEN THE THE RULE ACROSS MOST OF IDAHO SINCE THE 2005 WATER YEAR BEGAN ON OCTOBER 1ST 2004. THIS TREND CONTINUED DURING THE MONTH OF JANUARY 2005. THE NATIONAL DROUGHT MONITOR CONTINUES TO DEPICT EASTERN AND SOUTHERN IDAHO IN THE WORST SHAPE WITH SEVERE TO EXTREME DROUGHT. CENTRAL AND NORTHERN IDAHO HAVE DETERIORATED INTO MODERATE DROUGHT CONDITIONS. SPRING FLOOD POTENTIAL AND SEASONAL STREAM FLOW VOLUMES ARE ALL PROJECTED BELOW AVERAGE AT THIS POINT.
SNOW PACK...
SNOW PACK OBSERVATIONS ON FEBRUARY 9TH AT NRCS SNOTEL AND SNOW COURSE LOCATIONS ARE BELOW AVERAGE ACROSS THE ENTIRE STATE. NORTHERN IDAHO SNOWPACK IS NOW LESS THAN 50 PERCENT OF NORMAL. CENTRAL IDAHO SNOWPACK IS IN THE 50 TO 60 PERCENT OF NORMAL RANGE. SOUTHERN IDAHO SNOWPACK IS IN THE 70 TO 90 PERCENT RANGE.
LONG RANGE TEMPERATURE AND PRECIPITATION FORECASTS...
THE NATIONAL WEATHER SERVICE CLIMATE PREDICTION CENTER CONTINUES TO SHOW A HIGHER PROBABILITY THAT TEMPERATURES WILL AVERAGE ABOVE NORMAL OVER IDAHO DURING FEBRUARY THROUGH APRIL 2005. CONTINUED BELOW NORMAL PRECIPITATION IS THE MOST LIKELY SCENARIO IN IDAHO ESPECIALLY OVER THE NORTHERN HALF OF THE STATE FEBRUARY THROUGH APRIL 2005.
FLOOD POTENTIAL...
BASED ON CURRENT SNOW PACK AND SOIL MOISTURE CONDITIONS... THE THREAT OF SNOW MELT RELATED FLOODING IS BELOW AVERAGE. IN ADDITION... LOW ELEVATION SNOW PACK IS WELL BELOW NORMAL FURTHER REDUCING THE FLOOD THREAT IN STREAMS WHICH DERIVE MOST OF THEIR FLOW FROM LOW AND MID ELEVATIONS. IT IS IMPORTANT TO KEEP IN MIND THAT THIS IS AN EARLY SEASON ASSESSMENT WHICH MAY CHANGE SIGNIFICANTLY IF SNOW PACK INCREASES SIGNIFICANTLY OR AN UNUSUALLY HEAVY RAIN EVENT OCCURS.
PEAK SPRING FLOWS RESULTING FROM A NORMAL MELTING OF CURRENT AND PROJECTED SEASONAL SNOW PACK ARE LISTED IN THE FOLLOWING TABLE. LONG RANGE FORECASTS HAVE SOME MARGIN OF ERROR AND A REASONABLE RANGE OF POSSIBLE VALUES IS LISTED FOR PLANNING PURPOSES.
STREAM AND LOC. FLOOD STAGE FORECAST REASONABLE RANGE
SNAKE RIVER HEISE ID 24500 CFS 18000 CFS 13800 - 22200 CFS SHELLEY ID 25600 CFS 16200 CFS 11800 - 20800 CFS
TETON RIVER ST ANTHONY ID 4750 CFS 2700 CFS 1700 - 3700 CFS
HENRYS FORK ST ANTHONY ID 9000 CFS 5500 CFS 4400 - 6700 CFS REXBURG ID 9.5 FEET 7.9 FEET 7.0 - 8.9 FEET
PORTNEUF RIVER POCATELLO ID 1140 CFS 600 CFS 300 - 900 CFS
BIG WOOD RIVER HAILEY ID 4000 CFS 1900 CFS 1300 - 2500 CFS
BRUNEAU RIVER HOT SPRINGS ID 3200 CFS 1700 CFS 800 - 2700 CFS
PAYETTE RIVER EMMETT ID 16000 CFS 5800 CFS 4200 - 7300 CFS
WEISER RIVER WEISER ID 8900 CFS 3500 CFS 1800 - 5300 CFS
SELWAY RIVER LOWELL ID 42300 CFS 19500 CFS 14900 - 24100 CFS
CLEAR WATER RIVER STITES ID 9600 CFS 4800 CFS 3100 - 6600 CFS ORIFINO ID 75000 CFS 37700 CFS 27800 - 47600 CFS
MIDDLE FORK SALMON MIDDLE FORK LODGE NONE 5.4 FEET 4.7 - 6.1 FEET
SALMON RIVER SALMON 14000 CFS 7000 CFS 5600 - 8400 CFS WHITE BIRD 99000 CFS 45000 CFS 34700 - 55400 CFS
COEUR D ALENE RIVER ENAVILLE 27000 CFS 7100 CFS 4600 - 9600 CFS CATALDO 21350 CFS 12700 CFS 10700 - 14700 CFS
ST JOE RIVER CALDER 25600 CFS 10200 CFS 6800 - 13600 CFS ST MARIES 32.5 FEET 32.0 FEET 31.5 - 33.5 FEET
VOLUME FORECASTS...
SEASONAL VOLUME FORECASTS COORDINATED BETWEEN THE NATIONAL WEATHER SERVICE AND THE NATURAL RESOURCES CONSERVATION SERVICE ARE BASED ON PRECIPITATION AND SNOW PACK OBSERVED UP UNTIL FEBRUARY 1ST AND ASSUME BELOW NORMAL PRECIPITATION WILL OCCUR DURING FEBRUARY AND THAT NORMAL PRECIPITATION WILL OCCUR DURING MARCH AND BEYOND. THE VOLUME FORECASTS AND PERCENT OF AVERAGE FOR SELECTED STREAMS AND LOCATIONS ARE LISTED BELOW. NOTE THAT THE VOLUME IS EXPRESSED IN THOUSANDS OF ACRE FEET.
STREAM AND LOCATION STATE PERIOD VOL %AVE
SNAKE RIVER
JACKSON LAKE INFLOW WY APR-JUL 570 70 PALISADES RES INFLOW WY APR-JUL 2340 70 HEISE ID APR-JUL 2480 70 SHELLY ID APR-JUL 3190 72 BLACKFOOT ID APR-JUL 3060 66 AMER. FALLS RES IN ID APR-JUL 1460 45 KING HILL ID APR-JUL 1480 49 MURPHY ID APR-JUL 1540 50 WEISER ID APR-JUL 2290 40 BROWNLEE RES INFLOW ID APR-JUL 2590 41 HELLS CANYON ID APR-JUL 2640 41
HENRYS FORK ASHTON ID APR-JUL 435 76 ST. ANTHONY ID APR-JUL 535 73 REXBURG ID APR-JUL 1150 74
TETON RIVER ST. ANTHONY ID APR-JUL 270 67
BIG LOST RIVER MACKAY RES INFLOW ID APR-JUL 97 68
WILLOW CREEK RIRIE RES INFLOW ID APR-JUL 42 49
PORTNEUF RIVER TOPAZ, ID ID APR-JUL 64 67
GOOSE CREEK OAKLEY RES INFLOW ID APR-JUL 20 69
BIG WOOD RIVER HAILEY ID APR-JUL 161 63 MAGIC RES INFLOW ID APR-JUL 148 51
LITTLE WOOD RIVER CAREY ID APR-JUL 57 66
BRUNEAU RIVER HOT SPRINGS ID APR-JUL 139 67
OWYHEE RIVER OWYHEE RES INFLOW OR MAR-JUL 305 50 OWYHEE RES OUTFLOW OR APR-JUL 8 4
BOISE RIVER TWIN SPRINGS ID APR-JUL 415 65 ANDERSON RNCH RES INF ID APR-JUL 340 63 BOISE ID APR-JUL 880 62 PARMA ID APR-JUL 152 26
MALHEUR RIVER DREWSEY OR MAR-JUL 56 51 BEULAH RES INFLOW OR MAR-JUL 41 51
PAYETTE RIVER HORSESHOE BEND ID APR-JUL 940 58 EMMETT ID APR-JUL 570 46
N.F. PAYETTE RIVER CASCADE RES INFLOW ID APR-JUL 310 63
DEADWOOD RIVER DEADWOOD RES INFLOW ID APR-JUL 84 63
WEISER RIVER WEISER ID APR-JUL 200 51
POWDER RIVER SUMPTER OR MAR-JUL 46 66
SALMON RIVER SALMON ID APR-JUL 590 69 WHITEBIRD ID APR-JUL 3940 67
CLEARWATER RIVER ORIFINO ID APR-JUL 3140 68 SPALDING ID APR-JUL 4980 67
N.F CLEARWATER RIVER DWORSHAK RES INFLOW ID APR-JUL 1750 66
PEND ORIELLE RIVER PEND ORIELLE LAKE IN ID APR-JUL 9350 73
COUR D ALENE RIVER ENAVEILLE ID APR-JUL 440 60 COEUR D ALENE LAKE IN ID APR-JUL 1470 58
ST JOE RIVER CALDER ID APR-JUL 705 62
THE IDAHO SPRING FLOOD OUTLOOK AND WATER SUPPLY FORECAST WILL UPDATED ON OR BEFORE MARCH 11TH 2005.
BREIDENBACH