Upper Bear River Basin (13)
June 1997

Snow
Snow has melted out sooner this year than last year. Snow water equivalent (SWE) at data sites in the Bear River above the Idaho State Line is 20 percent above average (21 percent less than last year) -- all the low level SNOTEL sites have melted out. SWE for the Bear River in Utah is estimated to be 18 percent more than average; that is about 21 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 24 percent of average (about 30 percent less than 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 May was about 7 percent less than average for the two reporting stations; this is about 49 percent less than May of last year. The year-to-date precipitation figure for the basin is 136 percent of average; this is about 13 percent more than last year.

Reservoir
Woodruff Narrows reservoir is full (57,300 acre feet)

Streamflow
The 50 percent chance stream flow yields are expected to be much above average in the Bear River drainage. The Bear River near the Utah State Line is expected to yield 160,000 acre feet; that is about 33 percent more than average. The Thomas Fork drainage is estimated to yield 42,000 acre feet or 40 percent more than normal for the May-September period. The 50 percent chance yield for Smiths Fork near Border is about 160,000 acre feet (47 percent more than normal) for the May-September period. The Bear River near Woodruff is expected to yield about 205,000 acre feet, about 38 percent more than normal for the April-July period and about 175,000 acre feet (39 percent above average) for the May-September period. 

==================================================================================================================================
                                                      UPPER BEAR RIVER BASIN
                                               Streamflow Forecasts - June 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            MAY-SEP       140       152    |      160       147    |       168       180            109
                                                                    |                       |
THOMAS FK nr WY-ID State Line        MAY-SEP        27        35    |       42       140    |        50        64             30
                                                                    |                       |
BEAR R nr UT-WY State Line           MAY-SEP       131       147    |      160       133    |       174       196            120
                                                                    |                       |
BEAR R nr Woodruff                   MAY-JUL        96       143    |      175       139    |       207       254            126
                                                                    |                       |
==================================================================================================================================
                         UPPER BEAR RIVER BASIN                         |                 UPPER BEAR RIVER BASIN
             Reservoir Storage (1000 AF) - End of May                   |        Watershed Snowpack Analysis - June 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                                NO REPORT               |   UPPER BEAR RIVER in Utah    3        81       118
                                                                        |
                                                                        |   SMITHS & THOMAS FORKS       3        70       124
                                                                        |
                                                                        |   BEAR RIVER abv ID line      6        79       120
                                                                        |
==================================================================================================================================
 * 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.
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