Upper Bear River Basin
January 1997

Snow
Snow water equivalent (SWE) at data sites in the Upper Bear River above the Idaho State Line is 206 percent of average. The Upper Bear River in Utah measured about 73 percent more SWE than average; that is about 75 percent more than last year at this time. In the Wyoming portion of the Bear River drainage, SWE in the Smiths and Thomas Forks is estimated to be about 220 percent of average and about 155 percent of last year. See the Basin Summary of Snow Course Data at the beginning of this report for more detailed information.

Precipitation
Precipitation for the month of December was very high. Three stations reported and the lowest was 211 percent of average, at Sage. The basin received 298 percent of average for the month. The year-to-date precipitation figure for the basin is 187 percent of average.

Reservoir
Data for the Woodruff Narrows Reservoir was not available this month.

Streamflow
Stream flow yields are expected to be above average in the Bear River drainage. The 50 percent chance April - September yield forecast for the Bear River at the Utah State Line is 160,000 acre feet which is about 27 percent more than average. The Thomas Fork drainage is estimated to yield 58,000 acre feet or 61 percent more than normal for the April - September period. The 50 percent chance yield for Smiths Fork near Border is about 175,000 acre feet (48 percent more than normal) for the April - September period.

==================================================================================================================================
                                                      UPPER BEAR RIVER BASIN
                                               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)
====================================================================|=======================|=====================================
SMITHS FORK nr Border, WY            APR-SEP       139       160    |      175       148    |       190       211            118
                                                                    |                       |
THOMAS FK nr WY-ID State Line        APR-SEP        28        43    |       58       161    |        78       121             36
                                                                    |                       |
BEAR R nr UT-WY State Line           APR-SEP       110       138    |      160       127    |       186       232            126
                                                                    |                       |
==================================================================================================================================
                         UPPER BEAR RIVER BASIN                         |                 UPPER BEAR RIVER BASIN
             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
========================================================================|=========================================================
WOODRUFF NARROWS                        57.3     30.2     44.0      --- |   UPPER BEAR RIVER in Utah    3       175       173
                                                                        |
                                                                        |   SMITHS & THOMAS FORKS       3       155       220
                                                                        |
                                                                        |   BEAR RIVER abv ID line      8       176       203
                                                                        |
==================================================================================================================================
 * 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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