Precipitation for January was generally well below average for the State. Year-to-date precipitation is below average for all except the Belle Fourche drainage - this area is still feeling the effects of the heavy snow last fall. Reservoir levels vary from about 61 percent of average to 188 percent of average. Generally, the larger capacity reservoirs are above average storage. Forecast runoff varies from 42 to 109 percent of average. The mean of all the forecast points in the State is about 67 percent of average (33percent below average).
Snowpack
Although the state received quite a bit of snow early, snowfall did not carry through the early part of the winter. SWE is generally below average for the entire State. SWE in the northwestern portion of the State is now at 51 percent of average (64 percent of last year). Northeast Wyoming SWE is currently about 73 percent of average (60 percent of last year). The southeast portion is currently about 77 percent of average SWE (95 percent of last year). And the southwest is about 67 percent of average (83 percent of last year).
Precipitation
January precipitation was well below normal over the entire State. The Belle Fourche and Little Snake basins received 46 percent of normal precipitation for January. These were the bright spots in the state as far as precipitation goes. Most of the basins received less than 20 percent of average precipitation. The following table displays the major river basins and their departure from normal for this month.
| Basin | Departure from normal | Basin | Departure from normal |
| Snake River | -82% | Upper North Platte River | -43% |
| Yellowstone & Madison | -80% | Lower North Platte River | -65% |
| Wind River | -87% | Little Snake River | -54% |
| Bighorn | -64% | Upper Green River | -86% |
| Shoshone & Clarks Fork | -88% | Lower Green River | -84% |
| Powder & Tongue River | -63% | Upper Bear River | -83% |
| Belle Fourche & Cheyenne | -54% |
Streams
Stream flow yield is expected to be below average across the State. Most probable yield for the State is forecast to be about 67 percent of average (varies from 42 to 109 percent of average). The northwest part of the State is expected to yield about 61 percent of normal -- yield estimates vary from 42 to 75 percent of normal through the northwest region of the State. Yield from the northeast portion of Wyoming will be below average (about 75 percent of average) -- yield estimates vary from 49 to 109 percent of average for the various forecast points. The southeast portion of the state will be about 69 percent of normal -- yield estimates range from 62 to 77 percent of normal. The southwest portion of Wyoming varies from 47 to 85 percent of average -- mean estimated yield for the forecast points in southwest Wyoming is about 75 percent of average.
Reservoirs
Although several reservoirs did not report, reservoir storage for those reporting is generally above average for this time of the year. See following table for further information about reservoir storage.
Major Reservoirs in Wyoming
B A S I N W I D E
R E S E R V O I R S U M M A R Y
FOR THE END OF JANUARY 2001
BASIN AREA CURRENT AS LAST YR AS AVERAGE AS CURRENT AS CURRENT AS
RESERVOIR % CAPACITY % CAPACITY % CAPACITY % AVERAGE % LAST YR
--------------------------------------------------------------------------------
ALCOVA 85 85 85 100 100
ANGOSTURA 72 89 80 90 81
BELLE FOURCHE 81 97 57 142 83
BIG SANDY NO REPORT
BIGHORN LAKE 64 69 62 103 92
BOYSEN 75 89 97 77 84
BUFFALO BILL 57 69 64 89 82
BULL LAKE 41 63 57 72 66
DEERFIELD 99 98 84 118 101
EDEN NO REPORT
FLAMING GORGE AVERAGE NOT ESTABLISHED
FONTENELLE 35 49 57 61 72
GLENDO 56 65 65 86 87
GRASSY LAKE 84 82 71 118 102
GUERNSEY 28 29 15 188 97
HEBGEN LAKE 79 86 65 121 92
JACKSON LAKE 75 76 57 132 98
KEYHOLE 82 89 51 161 92
PACTOLA 100 98 83 120 102
PALISADES 46 88 75 61 52
PATHFINDER 72 92 54 132 78
PILOT BUTTE 74 71 52 142 104
SEMINOE 67 82 46 146 82
SHADEHILL 49 29 60 82 173
TONGUE RIVER 50 54 40 125 93
VIVA NAUGHTON RES NO REPORT
WHEATLAND #2 34 67 41 85 52
WOODRUFF NARROWS AVERAGE NOT ESTABLISHED
GLENDO PROJECT USERS 74 85 65 114 88
KENDRICK PROJECT 81 82 68 119 98
NORTH PLATTE PROJ 55 89 57 97 62
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