Upper Bear River Basin (13)
February 1998

Snow
Snow water equivalent (SWE), at data sites in the Bear River above the Idaho State Line, is 98 percent of average (52 percent less than last year). SWE for the Bear River in Utah is estimated to be 88 percent of average; that is about 51 percent less than last year at this time. SWE in the Wyoming portion of the Bear River drainage (Smiths and Thomas Forks) is estimated to be 98 percent of average (52 percent of last year at this time.). See the Basin Summary of Snow Course Data at the beginning of this report for more detailed information.

Precipitation
Precipitation for the month of January was 151 percent of average for the three reporting stations; this is 103 percent of January last year. The year-to-date precipitation figure for the basin is 86 percent of average; this is 50 percent of last year.

Reservoir
Woodruff Narrows reservoir had no report this month.

Streamflow
The 50 percent chance stream flow yields are expected to be below average in the Bear River drainage. The Bear River near the Utah - Wyoming State Line is expected to yield 102,000 acre feet; that is 81 percent of average. The Thomas Fork drainage is estimated to yield 27,000 acre feet or 75 percent of normal for the April-September period. The 50 percent chance yield for Smiths Fork near Border is about 99,000 acre feet (84 percent of normal) for the April-September period. The Bear River near Woodruff is expected to yield 125,000 acre feet, about 81 percent of normal for the April-September period. 

==================================================================================================================================
                                                      UPPER BEAR RIVER BASIN
                                               Streamflow Forecasts - February 1, 1998
==================================================================================================================================
                                              |  <<====== 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 FK nr Border, WY              APR-SEP        67        85    |       99        84    |       116       146            118
                                                                    |                       |
THOMAS FK nr WY-ID State Line        APR-SEP      14.6        21    |       27        75    |        35        50             36
                                                                    |                       |
Bear R nr UT-WY State Line           APR-SEP        73        89    |      102        81    |       117       142            126
                                                                    |                       |
BEAR R nr Woodruff, UT               APR-SEP        67        97    |      125        81    |       161       233            154
                                                                    |                       |
==================================================================================================================================
                         UPPER BEAR RIVER BASIN                         |                 UPPER BEAR RIVER BASIN
             Reservoir Storage (1000 AF) - End of January               |        Watershed Snowpack Analysis - February 1, 1998
==================================================================================================================================
                                      Usable |  *** Usable Storage ***  |                            Number     This Year as % of
Reservoir                            Capacity|  This      Last          |   Watershed                  of       =================
                                             |  Year      Year     Avg  |                          Data Sites   Last Yr   Average
========================================================================|=========================================================
                                                                        |   UPPER BEAR RIVER in Utah    0         0         0
                                                                        |
                                                                        |   SMITHS & THOMAS FORKS       4        52        98
                                                                        |
                                                                        |   BEAR RIVER abv ID line      4        52        98
                                                                        |
==================================================================================================================================
 * 90%, 70%, 30%, and 10% chances of exceeding are the probabilities that the actual volume 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 volume - actual volume may be affected by upstream water management.
To February 1998 Basin Outlook Report Contents Page