Powder and Tongue River Basins (6)
January 2000

Snow
The Upper Tongue River drainage is 85 percent of normal (98 percent of last year). Goose Creek drainage is 67 percent of average (76 percent of last year). Clear Creek drainage is 103 percent of normal (95 percent of last year). Crazy Woman Drainage is 84 percent of normal (90 percent of last year). The Upper Powder River is 74 percent of normal (96 percent of last year). The Powder River basin snow water equivalent (SWE), in Wyoming, is about 85 percent of average (96 percent of last year). For more information see Basin Summary of Snow Courses at beginning of report.

Precipitation
December precipitation was 120 percent of average for the 11 reporting stations (123 percent of last year). Monthly percentages range from 19 to 580 percent of average. Precipitation for the year ranges from 35 to 100 percent of average. Year-to-date precipitation is about 80 percent of average in the basin; this is 66 percent of last year at this time.

Reservoir
Tongue River Reservoir did not report this month. The total reservoir capacity is about 68,000 acre feet. Detailed reservoir data is shown on the following page and on the reservoir storage summary at the beginning of this report.

Streamflow
The following runoff values are for the 50 percent probability during the April through September forecast period. The estimated yield for Tongue River near Dayton is 98,000 acre-feet (85 percent of normal). Water users on the Middle Fork near Barnum should have a yield near 11,800 acre-feet (60 percent of normal). The North Fork of the Powder near Hazelton should yield about 7,000 acre-feet (69 percent of normal). The estimated yield for Clear Creek near Buffalo is 31,000 acre-feet (80 percent of average). Rock Creek near Buffalo will yield about 17,500 acre-feet (73 percent of normal), and Piney Creek at Kearny should yield about 39,000 acre-feet (77 percent of average). 

==================================================================================================================================
                                                   POWDER & TONGUE RIVER BASINS
                                               Streamflow Forecasts - January 1, 2000
==================================================================================================================================
                                              |  <<====== 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)
====================================================================|=======================|=====================================
TONGUE RIVER nr Dayton (2)           APR-SEP        67        86    |       98        85    |       110       129            115
                                                                    |                       |
MIDDLE FORK POWDER nr Barnum         APR-SEP       4.1       8.7    |     11.8        60    |      14.9      19.5           19.7
                                                                    |                       |
NORTH FORK POWDER nr Hazelton        APR-SEP       4.4       6.0    |      7.0        69    |       8.0       9.6           10.1
                                                                    |                       |
CLEAR CREEK nr Buffalo               APR-SEP        22        28    |       31        80    |        35        40             39
                                                                    |                       |
ROCK CREEK nr Buffalo                APR-SEP      11.6      15.1    |     17.5        73    |      19.9        23             24
                                                                    |                       |
PINEY CREEK at Kearny                APR-SEP      13.5        29    |       39        77    |        49        65             51
                                                                    |                       |
==================================================================================================================================
                      POWDER & TONGUE RIVER BASINS                      |              POWDER & TONGUE RIVER BASINS
             Reservoir Storage (1000 AF) - End of December              |        Watershed Snowpack Analysis - January 1, 2000
==================================================================================================================================
                                      Usable |  *** Usable Storage ***  |                            Number     This Year as % of
Reservoir                            Capacity|  This      Last          |   Watershed                  of       =================
                                             |  Year      Year     Avg  |                          Data Sites   Last Yr   Average
========================================================================|=========================================================
TONGUE RIVER                            68.0     35.9      5.8     26.0 |   UPPER TONGUE RIVER          5        98        85
                                                                        |
                                                                        |   GOOSE CREEK                 1        76        67
                                                                        |
                                                                        |   CLEAR CREEK                 2        95       103
                                                                        |
                                                                        |   CRAZY WOMAN CREEK           1        90        84
                                                                        |
                                                                        |   UPPER POWDER RIVER          3        96        74
                                                                        |
                                                                        |   POWDER RIVER in WY          5        96        85
                                                                        |
==================================================================================================================================
 * 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.
(3) - Forecasts produced in cooperation with Alberta Forecasting Staff Canada
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