FGUS65 KSTR 052140 ESGNM TTAA00 KSLR DDHHMM NATIONAL WEATHER SERVICE COLORADO BASIN RIVER FORECAST CENTER SALT LAKE CITY UT APR 5, 2005 INTERNAL NWS PRODUCT FOR GUIDANCE PURPOSES ONLY SAN JUAN RIVER BASIN SPRING FLOOD POTENTIAL OUTLOOK The 2005 spring runoff flood potential remains above average for streams throughout the San Juan Basin. The Upper San Juan and Animas basins continue to have much above average snow pack.. The observed monthly precipitation for March was 88% of average. Snow water equivalents declined slightly to 148% in the upper San Juan, 134% in the Animas drainage and 140% for the San Juan Basin. Observed March monthly and seasonal streamflow numbers were 127% and 153% respectively. The spring runoff volume forecasts call for above average to much above average runoff. The median forecast from the sample population of 15 was 155% of average. The range was 123-359% of average. It is important to note that threat of spring floods due to snow melt runoff will largely be determined by hydrometeorological events occuring during the April through late May time frame. Computed peak flows for three selected points are as follows: 2004 2005 River/Site Peak/Date Fcst Peak Normal Peak Historic Peak CFS CFS Period CFS ___________ _________ _________ ___________ ____________ Animas - 3590, 6/8 6100 5/20 - 6/12 10700 Durango San Juan - Gage Removed, Forecast Discontinued Pagosa Springs San Juan - 4420, 4/6 12200 5/5 - 6/20 15600 Bluff CBRFC/BMB NNNN $$