Hydrologic Outlook
HYDROLOGIC OUTLOOK...CORRECTED
NATIONAL WEATHER SERVICE OMAHA/VALLEY NE
401 PM CDT THU JUN 2 2011
...SIGNIFICANT AND PROLONGED FLOODING LIKELY ALONG THE MISSOURI
RIVER...
IN THE PAST FEW WEEKS...THE UPPER MISSOURI BASIN HAS RECEIVED NEARLY
A YEAR`S WORTH OF RAINFALL. IN ADDITION...SNOW PACK RUNOFF YET TO
FULLY ENTER THE UPPER PORTION OF THE RIVER SYSTEM IS 140 PERCENT OF
NORMAL. THESE CONDITIONS ARE RESULTING IN MISSOURI BASIN RESERVOIRS
ACROSS EASTERN MONTANA AND THE DAKOTAS NEARING THEIR MAXIMUM LEVELS.
RECORD RELEASES HAVE BEGUN AT GAVINS POINT DAM LOCATED TO THE WEST OF
YANKTON SOUTH DAKOTA. CURRENT RELEASES ARE AROUND 80,000 CFS (CUBIC FEET PER SECOND)...AND WILL BE INCREMENTALLY INCREASED TO 150,000 CFS BY MID-JUNE. THE PREVIOUS HIGH RELEASE AT GAVINS POINT WAS 70,000 CFS IN 1997.
THESE EXTREMELY HIGH FLOWS...COMBINED WITH NORMAL RAINFALL...MAY
RESULT IN NEAR-RECORD FLOODING ALONG PORTIONS OF THE MISSOURI RIVER.
IN ADDITION...MANY LOCATIONS ON THE MISSOURI RIVER WILL REMAIN
FLOODED THROUGH JULY.
THE FOLLOWING TABLE IS THE LONG-RANGE MISSOURI RIVER FORECAST...
ASSUMING NORMAL SUMMER PRECIPITATION ALONG WITH THE EXPECTED PEAK
RELEASES OF 150,000 CFS FROM GAVINS POINT DAM. RECORD AND 2010 FLOOD
CRESTS HAVE BEEN INCLUDED FOR REFERENCE. THIS PRODUCT WILL BE UPDATED
FREQUENTLY AS THE LONG-RANGE FORECAST WILL LIKELY BE MODIFIED AS A
RESULT OF RAINFALL EVENTS AND POTENTIAL ADJUSTMENTS TO RELEASES AT
GAVINS POINT.
LOCATION FS LONG-RNG FORECAST(FT) RECORD(FT) 2010 CREST(FT)
-------- -- --------------------- ---------- --------------
SIOUX CITY 30 35 TO 37 44.28-1952 25.49
DECATUR 35 40 TO 42 32.31-1996 31.42
BLAIR 26.5 30 TO 32 33.50-1952 26.93
OMAHA 29 34 TO 36 40.20-1952 28.74
NEB. CITY 18 27 TO ABOVE 28* 27.66-1952 25.21
BROWNVILLE 33 43 TO ABOVE 44* 44.30-1993 42.89
RULO 17 25.5 TO ABOVE 27* 26.63-2010 26.63
FS = FLOOD STAGE
* = THE UPPER LIMIT FOR THESE SITES CANNOT BE DETERMINED DUE TO POTENTIAL UPSTREAM AND DOWNSTREAM LEVEE OVERTOPPINGS AND RAPIDLY CHANGING CHANNEL CONDITIONS.
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