Managing Water Resources for Climate Variability and Change Using SNOTEL Data

Seasonal snowpack throughout the West is vulnerable to year-to-year climate variability. SNOTEL observations of daily snow accumulation, snow loss, and air temperature can be exploited to create seasonal forecast products to estimate April 1 SWE and the rate of spring melt. The April 1 SWE forecasts are based on historical observations of late winter snowfall, while the spring melt forecasts are based on anticipated spring temperatures. These forecast products could be useful for managers since they are mathematically simple, provide lead-time for planning purposes, and are delivered in terms of hydrologically-useful variables (such as April 1 SWE) with easy-to-understand estimates of uncertainty. The transparency of the uncertainty information allows users to devise and examine climate-driven scenarios, which can incorporate their tolerance for risk. These forecast products can also be applied to longer timescales to consider the impact of warming on snow accumulation and melt. In this paper, forecast products for April 1 SWE and the rate of spring melt are presented for the Skagit watershed in the Washington Cascades. For the seasonal accumulation forecast, a skillful prediction range for April 1 SWE can be generated as early as February 1.