TY - Generic T1 - The NOHRSC SNODAS Snow Water Equivalent Determination on Mount St. Helens, Washington T2 - 75th Annual Western Snow Conference Y1 - 2007 A1 - Lea, J. KW - Mt. St. Helens, floods, eruption, Toutle River, SNODAS, SNOTEL, SWE AB - Mount St. Helens in Washington State erupted in 1980 with devastating results due to pyroclastic debris flows entraining large amounts of the existing snowpack on the mountain. With the renewed volcanic activity that began in October 2004, close monitoring of the snowpack is required. The total snowpack snow water equivalent (SWE) volume determined by the Natural Resources Conservation Service (NRCS) is used by other federal agencies to determine the flood size that could be expected from a rapid snowmelt flooding event from possible eruptive activity on the mountain. In the 2006 and 2007 water year, the National Weather Service (NWS) National Operational Hydrologic Remote Sensing Center (NOHRSC) Snow Data Assimilation System (SNODAS) model was used to determine the total amount of SWE on the mountain. In early May 2006, a series of intensive snow surveys undertaken by 7 teams around the mountain. This additional data was then ingested into the SNODAS model and slight changes in the gridded data and SWE total resulted. The snow survey improved the modeled snowpack, especially in the high elevation environment. JF - 75th Annual Western Snow Conference T3 - Proceedings of the 75th Annual Western Snow Conference PB - Western Snow Conference CY - Kailua-Kona, HI UR - sites/westernsnowconference.org/PDFs/2007Lea.pdf ER -