ARS | Publication request: EARLY FORECASTS OF SNOWMELT RUNOFF USING SNOTEL DATA IN THE UPPER RIO GRANDE BASIN

Submitted to: Western Snow Conference Proceedings
Publication Type: Proceedings
Publication Acceptance Date: April 1, 2003
Publication Date: April 21, 2003
Citation: Dewalle, D., Eismeier, J., Rango, A. 2003. Early forecasts of snowmelt runoff using SNOTEL data in the upper Rio Grande Basin. In: Proceedings of the Western Snow Conference, April 21-25, 2003, Scottsdale, Arizona. p. 17-22.

Interpretive Summary: Water management agencies, farmers, and ranchers need water supply forecasts for the Rio Grande basin as early as possible, preferring not to wait until March 1 or April 1 to make decisions. We examined whether regression equations using winter snow water equivalent data could provide useful snowmelt season forecasts. Surprisingly, forecasts using SNOTEL data on November 1 and December 1 gave as good as or better estimates of spring snowmelt runoff volumes than March 1 and April 1 SNOTEL data for most years. It seems that very early season forecasts (November or December) are possible in the upper Rio Grande basin that would be useful for agricultural planning purposes by farmers and ranchers, as well as operational water management agencies.

Technical Abstract: Forecasts using SNOTEL data on November 1 and December 1 gave the best estimates of spring snowmelt runoff volumes almost as frequently as forecasts on March 1 and April 1 for the upper Rio Grande basin in Colorado during 1983-2001. Forecasts for 2002, a record drought year, greatly overestimated flow volumes regardless of prediction month. Attempts at improving predictions using the El Nino/La Nina Southern Oscillation Index were not successful.