Precipitation for February was generally 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 30 percent of average to 159 percent of average. Generally, the larger capacity reservoirs are above average storage. Forecast runoff varies from 33 to 103 percent of average. The mean of all the forecast points in the State is about 62 percent of average (38 percent below average).
Snowpack
Near average snow during the month of February kept most of the SWE percentages
almost the same as last month. SWE is generally below average for the entire
State. SWE in the northwestern portion of the State is now at 56 percent of
average (65 percent of last year). Northeast Wyoming SWE is currently about 71
percent of average (88 percent of last year). The southeast portion is currently
about 80 percent of average SWE (88 percent of last year). And the southwest is
about 71 percent of average (79 percent of last year).
Precipitation
February precipitation was below normal over the State, except in the Black
Hills. The Belle Fourche received 113 percent of normal for February. This was
the bright spot in the state as far as precipitation goes. Most of the basins
received less than 80 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 | -30% | Upper North Platte River | -04% |
Yellowstone & Madison | -22% | Lower North Platte River | -20% |
Wind River | -27% | Little Snake River | -25% |
Bighorn | -20% | Upper Green River | -27% |
Shoshone & Clarks Fork | -10% | Lower Green River | -27% |
Powder & Tongue River | -26% | Upper Bear River | -24% |
Belle Fourche & Cheyenne | +13% |
Streams
Stream flow yield is expected to be below average across the State. Most probable
yield for the State is forecast to be about 62 percent of average (varies from 33
to 103 percent of average). The northwest part of the State is expected to yield
about 57 percent of normal -- yield estimates vary from 33 to 73 percent of
normal through the northwest region of the State. Yield from the northeast
portion of Wyoming will be below average (about 54 percent of average) -- yield
estimates vary from 47 to 64 percent of average for the various forecast points.
The southeast portion of the state will be about 76 percent of normal -- yield
estimates range from 61 to 103 percent of normal. The southwest portion of
Wyoming varies from 33 to 77 percent of average -- mean estimated yield for the
forecast points in southwest Wyoming is about 65 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 FEBRUARY 2001 BASIN AREA CURRENT AS LAST YR AS AVERAGE AS CURRENT AS CURRENT AS RESERVIOR % CAPACITY % CAPACITY % CAPACITY % AVERAGE % LAST YR -------------------------------------------------------------------------------- ALCOVA 85 85 85 100 100 ANGOSTURA 74 93 83 89 80 BELLE FOURCHE 87 97 63 137 89 BIG SANDY 14 0 48 30 0 BIGHORN LAKE 62 69 60 104 90 BOYSEN 73 88 93 78 82 BUFFALO BILL 56 68 61 93 82 BULL LAKE 41 63 56 74 66 DEERFIELD 99 97 87 114 103 EDEN 0 0 35 0 0 FLAMING GORGE AVERAGE NOT ESTABLISHED FONTENELLE 28 38 50 56 73 GLENDO 64 75 76 85 85 GRASSY LAKE 84 82 72 116 102 GUERNSEY 34 35 30 112 96 HEBGEN LAKE 78 85 66 119 92 JACKSON LAKE 75 77 57 133 98 KEYHOLE 82 90 53 157 92 PACTOLA 98 98 84 118 100 PALISADES 50 89 76 65 56 PATHFINDER 74 94 58 128 78 PILOT BUTTE 74 71 56 132 104 SEMINOE 64 79 40 159 81 SHADEHILL 49 66 61 79 74 TONGUE RIVER 49 54 44 111 91 VIVA NAUGHTON RES 73 81 66 112 90 WHEATLAND #2 34 71 44 79 49 WOODRUFF NARROWS AVERAGE NOT ESTABLISHED GLENDO PROJECT USERS 74 84 69 107 88 KENDRICK PROJECT 81 82 68 119 98 NORTH PLATTE PROJ 59 94 60 99 63