SLCESGNM TTAA00 KSLR DDHHMM NATIONAL WEATHER SERVICE COLORADO BASIN RIVER FORECAST CENTER SALT LAKE CITY UT APR 6, 2010 INTERNAL NWS PRODUCT FOR GUIDANCE PURPOSES ONLY SAN JUAN RIVER BASIN SPRING FLOOD POTENTIAL OUTLOOK The potential for spring 2010 flooding due to snowmelt in the San Juan Basin is not high at this time. Most rivers and streams over the upper portions of the San Juan, Navajo, Piedra, Animas and La Plata are forecast to remain below bankfull. Current snowpack as of April 1st for the entire San Juan Basin is 100 percent of average. March precipitation was 70 percent of average across the entire Basin, with seasonal totals since October 2009 at 105 percent of average. The volume forecast for the April-July runoff period is near average. It is also important to keep in mind that an extended period of high temperatures resulting in rapid snowmelt, or heavy rainfall during the peak flow period, may cause or exacerbate flood problems in any year. Specific spring peak flow forecasts (maximum mean daily flow) as of April 1st. Forecast peaks for this year are 50% exceedance values. For full probabilistic distributions of possible peaks, see: http://www.cbrfc.noaa.gov/product/peakpeak.cgi 2010 Normal Fcst 2009 Flood Bankfull Average Period Peak Peak Flow Flow Peak of River / Site (cfsd) (cfsd) (cfs) (cfs) (cfs) Peak ------------------ ------- ------- ------- ------- ------ ----------- San Juan - 2000 2560 6755 4987 2485 5/15 - 6/12 Pagosa Springs Animas - 3500 5010 9560 7083 4675 5/28 - 6/14 Durango Animas - 3600 5170 8810 6580 4900 5/31 - 6/15 Farmington San Juan - 7500* 5970 40250 29327 7340 5/21 - 7/4 Bluff * - Peak flow forecast on the San Juan below Navajo Reservoir include the most probable Spring Release of 21 days at 5,000 cfs. Currently, this will happen starting from around may 27th through june 18th, and possibly coincide with the Animas river peak. CBRFC NNNN $$