FGUS65 KSTR 061626 ESGNM TTAA00 KSLR DDHHMM NATIONAL WEATHER SERVICE COLORADO BASIN RIVER FORECAST CENTER SALT LAKE CITY UT JAN 6, 2011 INTERNAL NWS PRODUCT FOR GUIDANCE PURPOSES ONLY SAN JUAN RIVER BASIN SPRING FLOOD POTENTIAL OUTLOOK The 2011 spring runoff flood potential is not high at this time for streams throughout the San Juan River Basin. December precipitation was 210% of average while the observed water year precipitation to date is 125% of average. Snow water equivalent as of January 1 was 125% in the Upper San Juan and 135% in the Animas. The current volume forecasts for the April-July runoff period is near average. It is important to note that it is very early in the snow accumulation season and that the spring flood threat due to runoff will largely be determined by hydrometeorologic events that occur during the next several months. January 1st snow water equivalent is 55% of the average seasonal peak and our models assume near normal precipitation into the future. Although spring temperatures affect the pattern of snowmelt runoff and consequently the magnitude of peak flows, peak flows also roughly correspond to volumetric flows. Therefore, at this time, given normal temperatures and the lack of an intense, heavy rainfall event during peak runoff, peak flows are expected to be near normal. By the same token, an extended period of much above normal temperatures or heavy rainfall during the melt can cause or exacerbate flooding problems. CBRFC NNNN $$