Upper Bear River Basin (13)
January 1999

Snow
Snow water equivalent (SWE), at snow courses in the Bear River above the Idaho State Line, is 72 percent of average (123 percent of last year). SWE for the Bear River in Utah is estimated to be 61 percent of average; that is about 105 percent of last year at this time. SWE in the Wyoming portion of the Bear River drainage (Smiths and Thomas Forks) is estimated to be 89 percent of average (150 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 82 percent of average for the 3 reporting stations; this is 168 percent of the previous December. The monthly percentages range from 82 to 91 percent. The year-to-date precipitation, for the basin, is 83 percent of average; this is 142 percent of last year’s amount. Year to date percentages range from 79 to 87 percent.

Reservoir
Woodruff Narrows reservoir is currently storing 43,000 acre feet. There is no average established for Woodruff Narrows. The total capacity of the reservoir is 57,300 acre feet.

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 91,000 acre feet; that is 72 percent of average for the April through September period. The Thomas Fork drainage is estimated to yield 25,000 acre feet or 69 percent of normal for the April-September period. The 50 percent chance yield for Smiths Fork near Border is about 100,000 acre feet (85 percent of normal) for the April-September period. The Bear River near Woodruff is expected to yield 101,000 acre feet, about 68 percent of normal for the April-July period. 

==================================================================================================================================
                                                      UPPER BEAR RIVER BASIN
                                               Streamflow Forecasts - June 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-JUL        68        79    |       87        85    |        96       111            102
                                                                    |                       |
THOMAS FK nr WY-ID State Line        APR-JUL      17.5        23    |       27        82    |        32        42             33
                                                                    |                       |
Bear R nr UT-WY State Line           APR-JUL        95       102    |      107        93    |       112       120            115
                                     JUN-JUL        48        58    |       66        90    |        75        90             73
                                                                    |                       |
BEAR R nr Woodruff, UT               APR-JUL        96       119    |      137        92    |       158       195            149
                                     JUN-JUL        37        50    |       61        88    |        75       102             69
                                                                    |                       |
==================================================================================================================================
                         UPPER BEAR RIVER BASIN                         |                 UPPER BEAR RIVER BASIN
             Reservoir Storage (1000 AF) - End of May                   |        Watershed Snowpack Analysis - June 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        68        80
                                                                        |
                                                                        |   SMITHS & THOMAS FORKS       3        70        87
                                                                        |
                                                                        |   BEAR RIVER abv ID line      6        65        78
                                                                        |
==================================================================================================================================
 * 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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