Length of the Snow Season Map: All Scenarios

<hr /> <p> <span><strong>Deprecation Warning</strong>: On June 1 2026, this item will no longer be available. </span> For more information on transitioing layers visit: <a target='_blank' href='https://gis-kingcounty.opendata.arcgis.com/pages/inspect-gis-data-1' rel='nofollow ugc noopener noreferrer'>Update Deprecated Items | King County GIS Open Data</a> </p> <hr /><p><span style='font-weight:bold;'>A pre-configured, multi-layer web map for viewing all Length of Snow Season scenarios.</span> <span style='font-style:italic;'>(To launch the map from the Climate Change Open Data site, select &quot;View Metadata&quot; under the &quot;About&quot; heading, then look for the button labeled &quot;Open in Map Viewer&quot; to the upper right.)</span></p><p>The map layers depict historical, and projected changes in, Length of the Snow Season, which is defined as the number of days between the dates of 10% accumulation and of 90% melt, relative to annual maximum snow water equivalent (SWE). Results are shown only for watersheds with an average historical April 1st SWE of at least 0.4 inch. April 1st is the approximate current timing of peak annual snowpack in the mountains of the Northwest. Geographic units: HUC10. <br /></p><p>Map layer data include historical conditions (1970-1999) and the projected changes for ten global models. Two time periods are considered: the 2040s (2030-2059) and the 2080s (2070-2099), based on a moderate greenhouse gas scenario (A1B).<span style='font-style:italic;'> <br /></span></p><p>Data classes and symbology by Robert Norheim, Climate Impacts Group, based on the CMIP3 projections used in the IPCC 2007 report. </p><p>Data source: Hamlet et al. 2013.</p>