Snowpack
Snow conditions deteriorated across the State this last month. SWE is
generally just below average to well below average. SWE in the
northwestern portion of the State is now at 64 percent of average (51
percent of last year). Although the Black Hills is only 22 percent of
average, northeast Wyoming SWE is currently about 76 percent of
average (79 percent of last year). The Southeast portion saw a
decrease to 76 percent of average SWE (72 percent of last year). And
the southwest dropped to about 62 percent of average (53 percent of
last year).
Precipitation
April precipitation was below normal across most of the State. The
Belle Fourche and Lower North Platte River drainges were above normal,
and the Big horn and Powder River drainages were near normal. The
following table displays the major river basins and their departure
from normal for April 2000.
| Basin | Departure from normal | Basin | Departure from normal |
| Snake River | -29% | Upper North Platte River | -17% |
| Yellowstone & Madison | -09% | Lower North Platte River | +20% |
| Wind River | -07% | Little Snake River | -38% |
| Bighorn | +01% | Upper Green River | -42% |
| Shoshone & Clarks Fork | -17% | Lower Green River | -36% |
| Powder & Tongue River | 00% | Upper Bear River | -26% |
| Belle Fourche & Cheyenne | +53% |
Streams
Stream flow yield is expected to be below average across the State.
The northwest part of the State is expected to yield about 70 percent
of normal -- yield estimates vary from 48 to 89 percent of normal
through the northwest region of the State. Yield from the northeast
portion of Wyoming will be below average (about 65 percent of average)
-- yield estimates vary from 33 to 85 percent of average for the
various forecast points. In most cases, the southeast portion of the
state will be about 68 percent of normal -- yield estimates range from
41 to 102 percent of normal. The southwest portion of Wyoming varies
from 53 to 82 percent of average -- mean estimated yield for the
forecast points in southwest Wyoming is about 67 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.
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 APRIL 2000
BASIN AREA CURRENT AS LAST YR AS AVERAGE AS CURRENT AS CURRENT AS
RESERVOIR % CAPACITY % CAPACITY % CAPACITY % AVERAGE % LAST YR
--------------------------------------------------------------------------------
ALCOVA 107 97 98 110 110
ANGOSTURA 99 99 93 106 100
BELLE FOURCHE 106 103 82 130 104
BIG SANDY NO REPORT
BIGHORN LAKE 65 57 58 111 114
BOYSEN 84 80 84 100 106
BUFFALO BILL 67 56 52 129 119
BULL LAKE 62 66 53 117 94
DEERFIELD 100 101 89 112 99
EDEN NO REPORT
ENNIS LAKE 78 81 86 91 97
FLAMING GORGE AVERAGE NOT ESTABLISHED
FONTENELLE 34 39 47 73 88
GLENDO 102 104 90 113 98
GRASSY LAKE 86 88 77 111 97
GUERNSEY 79 82 72 110 97
HEBGEN LAKE 81 61 65 124 133
JACKSON LAKE 85 63 54 157 134
KEYHOLE 91 96 57 160 94
PACTOLA 100 101 87 115 99
PALISADES 83 40 68 122 209
PATHFINDER 98 98 60 163 100
PILOT BUTTE 79 61 95 83 130
SEMINOE 74 71 39 192 105
SHADEHILL 69 96 80 86 72
TONGUE RIVER 60 40 54 112 151
VIVA NAUGHTON RES 89 69 62 142 129
WHEATLAND #2 78 77 56 140 101
WOODRUFF NARROWS AVERAGE NOT ESTABLISHED
GLENDO PROJECT USERS 94 94 70 134 100
KENDRICK PROJECT 87 86 67 130 102
NORTH PLATTE PROJ 101 100 74 136 101
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