Powder and Tongue River Basins
January 1997

Snow
The basin is in good shape as far as snowpack is concerned. All drainages within the Powder and Tongue River basin are above average. The entire basin in Wyoming is now about 136 percent of average Snow Water Equivalent (SWE). The upper Tongue River drainage is about 27 percent above normal; the Goose Creek drainage is about 10 percent ahead of normal; the Clear Creek drainage is about 55 percent above normal; the Crazy Woman Drainage is about 27 percent above normal, and the Powder River drainage is about 36 percent above normal. The Powder River basin is also ahead of last year at this time by 34 percent. For more information see Basin Summary of Snow Courses at beginning of report.

Precipitation
Year-to-date precipitation is about 21 percent above average in the basin; this is 16 percent better than it was last year at this time. December precipitation was 56 percent of average (179 percent more than last year). Kaycee was the only reporting station that came in below average for the month, 83 percent. Bruneau December precipitation was about 252 percent of average.

Reservoir
There was no report for Tongue River Reservoir this month.

Streamflow
The following values are for the 50 percent probability during the April to September forecast period. The Tongue River near Dayton is estimated to yield 125,000 acre feet (25 percent above normal). Water users on the Middle Fork near Barnum should have a yield near 21,300 acre feet (8 percent above normal). The North Fork near Hazelton should yield about 12,000 acre feet (19 percent above normal). Clear Creek near Buffalo is estimated to yield 51,000 acre feet (31 percent above average). Rock Creek near Buffalo will yield about 27,000 acre feet (13 percent above normal) and Piney Creek at Kearny should yield about 61,000 acre feet (20 percent above average). 

==================================================================================================================================
                                                   POWDER & TONGUE RIVER BASINS
                                               Streamflow Forecasts - January 1, 1997
==================================================================================================================================
                                              |  <<====== Drier ======  Future Conditions  =======  Wetter =====>>  |             
                                              |                                                                     |
  Forecast Point                     Forecast |  ==================== Chance Of Exceeding * ======================  |
                                      Period  |    90%       70%    |  50% (Most Probable)  |      30%       10%    |  30-Yr Avg.
                                              | (1000AF)  (1000AF)  |   (1000AF)  (% AVG.)  |    (1000AF)  (1000AF) |    (1000AF)
====================================================================|=======================|=====================================
TONGUE RIVER near Dayton (2)         APR-SEP        96       113    |      125       109    |       137       154            115
                                                                    |                       |
MIDDLE FORK POWDER near Barnum       APR-SEP      13.3      18.1    |       21       108    |        25        29           19.7
                                                                    |                       |
NORTH FORK POWDER near Hazelton      APR-SEP       9.0      10.8    |     12.0       119    |      13.2      15.0           10.1
                                                                    |                       |
CLEAR CREEK near Buffalo             APR-SEP        45        48    |       51       131    |        54        58             39
                                                                    |                       |
ROCK CREEK near Buffalo              APR-SEP        22        25    |       27       113    |        29        33             24
                                                                    |                       |
PINEY CREEK at Kearny                APR-SEP        39        52    |       61       120    |        70        83             51
                                                                    |                       |
==================================================================================================================================
                      POWDER & TONGUE RIVER BASINS                      |              POWDER & TONGUE RIVER BASINS
             Reservoir Storage (1000 AF) - End of December              |        Watershed Snowpack Analysis - January 1, 1997
==================================================================================================================================
                                      Usable |  *** Usable Storage ***  |                            Number     This Year as % of
Reservoir                            Capacity|  This      Last          |   Watershed                  of       =================
                                             |  Year      Year     Avg  |                          Data Sites   Last Yr   Average
========================================================================|=========================================================
TONGUE RIVER                                    NO REPORT               |   UPPER TONGUE RIVER          5       110       127
                                                                        |
                                                                        |   GOOSE CREEK                 1        95       110
                                                                        |
                                                                        |   CLEAR CREEK                 2       117       155
                                                                        |
                                                                        |   CRAZY WOMAN CREEK           1        95       124
                                                                        |
                                                                        |   UPPER POWDER RIVER          4       145       127
                                                                        |
                                                                        |   POWDER RIVER in WY          6       134       136
                                                                        |
==================================================================================================================================
 * 90%, 70%, 30%, and 10% chances of exceeding are the probabilities that the actual flow will exceed the volumes in the table.

The average is computed for the 1961-1990 base period.

(1) - The values listed under the 10% and 90% Chance of Exceeding are actually 5% and 95% exceedance levels.                  
(2) - The value is natural flow - actual flow may be affected by upstream water management.
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