Snowpack
Conditions vary across the State as of April 1. The northwest and western
portions of the State are near average to well above average. The Shoshone
and Upper Yellowstone Basins are well above average. Snow water equivalents
(SWE) in the southern and eastern areas of Wyoming vary from slightly above
average to below average. Precipitation, snow at the higher elevations,
tapered off significantly this month over the entire State.
Precipitation
All the basins, except one, received below average precipitation for the
month of March. Eleven of the 13 basins received less than 90 percent of
average precipitation for the month. The following table displays the major
river basins and their departure from normal for March 1999.
| Basin | Departure from normal | Basin | Departure from normal |
| Snake River | -27% | Upper North Platte River | -46% |
| Yellowstone & Madison | -20% | Lower North Platte River | -53% |
| Wind River | -40% | Little Snake River | -44% |
| Bighorn | -35% | Upper Green River | -22% |
| Shoshone & Clarks Fork | -35% | Lower Green River | +25% |
| Powder & Tongue River | -24% | Upper Bear River | -09% |
| Belle Fourche & Cheyenne | -30% |
Streams
Runoff is expected to vary greatly across the state. Yield from the northeast
portion of Wyoming should be slightly average -- yield estimates vary from
79 to 101 percent of average (mean is 88%). In most cases, the southeast
portion of the state will be about 15 percent below normal -- yield
estimates range from 35 to 114 percent of normal. The southwest portion of
Wyoming varies from 81 to 111 percent of average -- mean estimated yield
for southeast Wyoming is 100 percent of average. Portions of the Bear
River are expected to produce about 19 percent below normal volume of runoff.
The northwest part of the State is expected to yield about 12 percent more
than normal -- yields vary from 93 to 124 percent of normal.
Reservoirs
Reservoir storage is generally above average for this time of the year.
See following table for further information about reservoir storage.
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 MARCH 1999
BASIN AREA CURRENT AS LAST YR AS AVERAGE AS CURRENT AS CURRENT AS
RESERVIOR % CAPACITY % CAPACITY % CAPACITY % AVERAGE % LAST YR
------------------------------------------------------------------------------
ALCOVA 88 86 88 100 102
ANGOSTURA 99 99 90 110 100
BELLE FOURCHE 101 101 73 137 100
BIG SANDY 99 64 52 190 153
BIGHORN LAKE 58 63 59 98 91
BOYSEN 79 86 89 90 93
BUFFALO BILL 62 80 56 112 78
BULL LAKE 64 62 55 117 103
DEERFIELD 101 101 89 113 100
EDEN 60 30 40 151 203
ENNIS LAKE 76 72 81 93 105
FLAMING GORGE AVERAGE NOT ESTABLISHED
FONTENELLE 36 34 46 78 106
GLENDO 100 89 83 120 112
GRASSY LAKE 87 50 74 118 174
GUERNSEY 66 69 47 138 96
HEBGEN LAKE 68 70 65 105 98
JACKSON LAKE 70 77 56 126 92
KEYHOLE 94 94 56 169 100
PACTOLA 98 98 85 115 100
PALISADES 51 70 72 70 73
PATHFINDER 96 98 61 157 98
PILOT BUTTE 70 69 68 103 102
SEMINOE 66 75 36 183 88
SHADEHILL 94 78 78 122 121
TONGUE RIVER 18 14 53 34 129
VIVA NAUGHTON RES 70 54 64 110 130
WHEATLAND #2 67 71 49 136 94
WOODRUFF NARROWS AVERAGE NOT ESTABLISHED
GLENDO PROJECT USERS 92 92 69 133 100
KENDRICK PROJECT 81 78 68 120 104
NORTH PLATTE PROJ 94 101 64 148 93
To April 1999 Basin Outlook Report Contents Page