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- 4 - . There will be alternating wet/cold and warm/dry periods likely for April and May. June looks stormy too! The graphic of northern Hemispheric wave patterns, shows storms and warm periods lined up for the springtime. It takes about 8 weeks for these to cycle around the planet. . There is a warm mass of air over the Gulf of Mexico, with a large ridge of warm air developing underneath it. . The Absence of extended hot, dry period in April, May and June should slow the runoff and eliminate threat of a "sudden runoff gusher". Summary of Flood threat . East of the Divide, if spring rains/snows arrive as forecast, a greater threat of river flooding could develop in the South Platte basin between May I and June 15. . Arkansas River could see a brief flood threat in May if a general spring storm produces runoff from Palmer Divide and the Sangre De Cristo's. . Watch out for Palmer Divide thunderstorm rain event (... a mini June 16/17 1965....) in early -mid June. The next 10-12 weeks will be quite stormy and cool with above normal precipitation and a relatively cool spring. . Most mountain basins will achieve normal SWE and some will be 130%-150%+ of normal (Gunnison, San Miguel, Rio Grande, Dolores, Animas and San Juan). No extended hot, dry periods(>5 days) before Memorial Day means an on-off snowmelt slowed by stormy periods. Stream flow/reservoir stora2:e (Jack Byer's - Division of Water Resources) . Its too early to look at stream hydrographs and to report on them. Streamflows in certain portions ofthe state are a little higher than average, but that doesn't necessarily equate to future flooding. . Grand Mesa there is 156% of average snowpack, and officials are working with local reservoir company to dig out some of the spillway to prevent a snow dam. Next week the DWR will be flying over the Mesa to look at some ofthe reservoirs. They are not concerned with filling but the operation is geared towards using the reservoirs to mitigate the runoff. Diversions are going to be geared up to divert full amount if needed. . The snowpack creates a good opportunity to fill reservoirs and can recharge the aquifer in the San Luis Valley. . DWR has over 60 alert sites that show rate of change, low and high water and they cooperate with CWCB for flood warning stream gages. DWR is tying into to USGS gages, now have hourly basis and random readings available on both websites. These gages provide a pager alert to CWCB and SEO staff. . Denver Water and Aurora reservoirs are not full or projected to fill, but irrigation reservoirs are generally full. . The State Engineers Surface Water Supply Index (SWSI) report can be found at htto:I /water. state .co .us/pubs/swsi .asp "Streamflow estimates for 2005 Runoff season" (Geor2:e Leavesley - USGS) . This was a PowerPoint presentation by George Leavesley of the USGS, Watershed and River Systems Management Program Flood Protection . Water Project Planning and Finance. Stream and Lake Water Supply Protection. Conservation Planning