Powder and Tongue River Basins
February 1997

Snow
The basin is in good shape as far as snowpack is concerned. All drainage's within the Powder and Tongue River basin are above average. The entire basin, in Wyoming, is now about 129 percent of average Snow Water Equivalent (SWE). The upper Tongue River drainage is about 23 percent above normal; the Goose Creek drainage is about 15 percent ahead of normal; the Clear Creek drainage is 32 percent above normal; the Crazy Woman Drainage is 19 percent above normal. 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 14 percent better than it was last year at this time. January precipitation was 27 percent above average (9 percent more than last year). Kaycee and Hansen Sawmill were the only reporting stations that came in below average for the month. January precipitation for Bruneau was 295 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 130,000 acre feet (13 percent above normal). Water users on the Middle Fork near Barnum should have a yield near 23,000 acre feet (17 percent above normal). The North Fork near Hazelton should yield about 11,500 acre feet (14 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 26,000 acre feet (8 percent above normal) and Piney Creek at Kearny should yield about 65,000 acre feet (128 percent above average). 

==================================================================================================================================
                                                   POWDER & TONGUE RIVER BASINS
                                               Streamflow Forecasts - February 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       101       118    |      130       113    |       142       159            115
                                                                    |                       |
MIDDLE FORK POWDER near Barnum       APR-SEP      15.8        20    |       23       117    |        26        30           19.7
                                                                    |                       |
NORTH FORK POWDER near Hazelton      APR-SEP       8.8      10.4    |     11.5       114    |      12.6      14.2           10.1
                                                                    |                       |
CLEAR CREEK near Buffalo             APR-SEP        44        48    |       51       131    |        54        58             39
                                                                    |                       |
ROCK CREEK near Buffalo              APR-SEP        21        24    |       26       108    |        28        32             24
                                                                    |                       |
PINEY CREEK at Kearny                APR-SEP        42        56    |       65       128    |        74        88             51
                                                                    |                       |
==================================================================================================================================
                      POWDER & TONGUE RIVER BASINS                      |              POWDER & TONGUE RIVER BASINS
             Reservoir Storage (1000 AF) - End of January               |        Watershed Snowpack Analysis - February 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                            68.0     18.4     22.4     27.1 |   UPPER TONGUE RIVER          9       109       123
                                                                        |
                                                                        |   GOOSE CREEK                 3       108       115
                                                                        |
                                                                        |   CLEAR CREEK                 3        99       132
                                                                        |
                                                                        |   CRAZY WOMAN CREEK           2       108       120
                                                                        |
                                                                        |   UPPER POWDER RIVER          5       143       128
                                                                        |
                                                                        |   POWDER RIVER in WY          8       124       129
                                                                        |
==================================================================================================================================
 * 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.
To February 1997 Basin Outlook Report Contents Page