Snowpack
Snowpack over the State varied from above normal to well below normal. The
storm in the Black Hills area brought their snow water equivalent to just
below normal, and the snowpack depth to well above normal in some places.
The northwest portion of the State is generally slightly below normal with
some individual locations well above normal. SWE in the northeast part of
Wyoming is 5-10 percent below normal. The southeast portion of the State
ended up near normal to 90 percent of normal at the end of February.
Generally, the southwest part of the State is 5 to 10 percent below
average; the Henrys Fork drainage was about 39 percent above normal. The
Bear River drainage appears to have just below normal SWE.
Precipitation
Basins across Wyoming received below average precipitation, except in the
Black Hills. February precipitation in the Black Hills was 232 percent of
average for the month -- mostly because of one storm at the end of the
month. Eight of the 13 basins were below average for the month of
February. The following table displays the major river basins and their
departure from normal.
| Basin | Departure from normal |
Basin | Departure from normal |
| Snake | -48% | Upper North Platte River | -1% |
| Yellowstone & Madison | -50% | Lower North Platte | -1% |
| Wind River | -43% | Little Snake River | +24% |
| Big Horn | +7% | Upper Green River | -55% |
| Shoshone & Clarks Fork | -63% | Lower Green River | -32% |
| Powder & Tongue River | +15% | Upper Bear River | +1% |
| Belle Fourche & Cheyenne | +232% |
Streams
Runoff is expected to vary from average to just below average across the
state. The northwestern part of the state is expected to have yields
varying from average to about 10 percent below average. The northeast
portion of Wyoming varies from near average to about 20 percent below
average. In most cases, the southeast portion of the state will be near
average to about 15 percent below normal (as much as 20 percent below
normal in the lower portion of the Platte River drainage). The southwest
varies from above average on the Blacks Fork drainage to 79 percent of
average in the Big Sandy River drainage and 10- 15 percent below average
on the Bear River drainage.
Reservoirs
Reservoir storage varies from well below to well above average, however,
the majority are above average for this time of the year. Even a below
average runoff should fill most reservoirs. 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 1998
BASIN AREA CURRENT AS LAST YR AS AVERAGE AS CURRENT AS CURRENT AS
RESERVIOR % CAPACITY % CAPACITY % CAPACITY % AVERAGE % LAST YR
--------------------------------------------------------------------------------
ALCOVA 86 86 85 100 100
ANGOSTURA 98 99 83 117 99
BELLE FOURCHE 99 96 63 156 104
BIG SANDY 62 42 48 130 148
BIGHORN LAKE 64 56 60 107 114
BOYSEN 89 88 93 96 101
BUFFALO BILL 81 75 61 134 108
BULL LAKE 63 53 56 112 117
DEERFIELD 100 96 87 115 104
EDEN 30 31 35 85 97
ENNIS LAKE 71 69 83 86 104
FLAMING GORGE AVERAGE NOT ESTABLISHED
FONTENELLE 39 35 50 78 113
GLENDO 88 74 76 117 120
GRASSY LAKE 51 87 72 71 59
GUERNSEY 53 39 30 179 136
HEBGEN LAKE 72 65 66 109 110
JACKSON LAKE 77 77 57 135 100
KEYHOLE 91 84 53 173 108
PACTOLA 98 96 84 117 101
PALISADES 86 61 76 113 141
PATHFINDER 96 87 58 165 109
PILOT BUTTE 69 74 56 123 92
SEMINOE 82 66 40 205 125
SHADEHILL 69 51 61 112 134
TONGUE RIVER 10 34 44 23 30
VIVA NAUGHTON RES 55 0 66 84 0
WHEATLAND #2 64 56 44 146 115
WOODRUFF NARROWS AVERAGE NOT ESTABLISHED
GLENDO PROJECT USERS 86 87 69 125 99
KENDRICK PROJECT 84 82 68 123 103
NORTH PLATTE PROJ 97 76 60 163 127
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