The NOHRSC SNODAS Snow Water Equivalent Determination on Mount St. Helens, Washington

TitleThe NOHRSC SNODAS Snow Water Equivalent Determination on Mount St. Helens, Washington
Publication TypeConference Proceedings
Year of Conference2007
AuthorsLea, J.
Conference Name75th Annual Western Snow Conference
Series TitleProceedings of the 75th Annual Western Snow Conference
Date PublishedApril 2007
PublisherWestern Snow Conference
Conference LocationKailua-Kona, HI
KeywordsMt. St. Helens, floods, eruption, Toutle River, SNODAS, SNOTEL, SWE
Abstract

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.

URLsites/westernsnowconference.org/PDFs/2007Lea.pdf