Upper Bear River Basin (13)
January 1998

Snow
Snow water equivalent (SWE), at data sites in the Bear River above the Idaho State Line, is 59 percent of average (72 percent less than last year). SWE for the Bear River in Utah is estimated to be 58 percent of average; that is about 67 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 about 59 percent of average (about 73 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 December was about 49 percent of average for the three reporting stations; this is about 17 percent of December last year. The year-to-date precipitation figure for the basin is 59 percent of average; this is about 32 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 State Line is expected to yield 87,000 acre feet; that is about 74 percent of average. The Thomas Fork drainage is estimated to yield 20,000 acre feet or 56 percent of normal for the April-September period. The 50 percent chance yield for Smiths Fork near Border is about 89,000 acre feet (71 percent of normal) for the April-September period. The Bear River near Woodruff is expected to yield about 100,000 acre feet, about 65 percent of normal for the April-September period. 

==================================================================================================================================
                                                      UPPER BEAR RIVER BASIN
                                               Streamflow Forecasts - January 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        52        71    |       87        74    |       107       145            118
                                                                    |                       |
THOMAS FK nr WY-ID State Line        APR-SEP       9.6      14.8    |       20        56    |        27        42             36
                                                                    |                       |
Bear R nr UT-WY State Line           APR-SEP        62        77    |       89        71    |       103       128            126
                                                                    |                       |
BEAR R nr Woodruff, UT               APR-SEP        49        75    |      100        65    |       133       203            154
                                                                    |                       |
==================================================================================================================================
                         UPPER BEAR RIVER BASIN                         |                 UPPER BEAR RIVER BASIN
             Reservoir Storage (1000 AF) - End of December              |        Watershed Snowpack Analysis - January 1, 1998
==================================================================================================================================
                                      Usable |  *** Usable Storage ***  |                            Number     This Year as % of
Reservoir                            Capacity|  This      Last          |   Watershed                  of       =================
                                             |  Year      Year     Avg  |                          Data Sites   Last Yr   Average
========================================================================|=========================================================
WOODRUFF NARROWS                                NO REPORT               |   UPPER BEAR RIVER in Utah    3        33        58
                                                                        |
                                                                        |   SMITHS & THOMAS FORKS       3        27        59
                                                                        |
                                                                        |   BEAR RIVER abv ID line      6        28        59
                                                                        |
==================================================================================================================================
 * 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 January 1998 Basin Outlook Report Contents Page