Laserfiche WebLink
<br />v. COLORADO FLOOD FORECAST MODEL <br /> <br />Following the first flood task force meeting on May 7, 1995, the CWCB staff made a <br />commitment to evaluate methods and models to better forecast flood peaks and times. The <br />Board did not have the budget nor the time to develop a complex computer model that existed <br />in other states. In addition, the staff began receiving calls from local floodplain admini~trators <br />and emergency managers regarding the 1995 flood threat. The callers usually accompanied their <br />inquires by a request of "when will the flood. peak occur:'? <br /> <br />In response to these requests and with knowledge on past flood events, the CWCB staff <br />investigated methods of flood forecasting using readily available resources and known <br />characteristics for snowmelt runoff. Certain basic characteristics and runoff parameters do exist <br />for snowmelt runoff and. the resultant flooding conditions. In developing a forecast model, the <br />following characteristics and issues must be addressed. <br /> <br />· The basic elements/parameters for snowmelt flood forecasting are: <br /> <br />- Daily snowpack equivalent water content data as compared to the twenty year average; <br /> <br />- Temperature information including the daily, the 7- day forecast. and the <br />30- day forecast data; <br /> <br />- Selected stream gage data for the basins and stream locations being monitored; <br /> <br />- Daily precipitation information and data from rainfall and snowfall for the 24- hour <br />forecast period, and <br /> <br />- Compute unit runoff values versus temperature for a given weather pattern/trend for <br />historical regional flood events. <br /> <br />· The basic snowmelt characteristics that must exist to produce snowmelt runoff flooding <br />are: <br /> <br />- Must have night time temperatures that are above freezing; <br /> <br />- Snowpack line must lie within the elevation range of 9.500 feet m.sJ. to 10,500 feet <br />m.s.!.; <br /> <br />- A weather forecast for a 5- to 7- day high temperature range of 85 to 95 degree <br />fahreoheit; <br /> <br />- A basin snowpack percentage which is 150 percent above the 20- year average; and <br /> <br />'I <br /> <br />- A basin water content value of 10 inches or more at the 10,000 foot elevation during <br />the time of the heat wave. <br />