TY - Generic T1 - Spatial and temporal snowpack variation in the crown of the contintent ecosystem T2 - 70th Annual Western Snow Conference Y1 - 2002 A1 - Selkowitz, D.J. A1 - Fagre, D.B. A1 - Reardon, B.A. KW - Snowpack, Crown of the Continent Ecosystem, SNOTEL, PDO AB - Snowpack related ecosystem changes such as glacier recession and alpine treeline advance have been documented in the Crown of the Continent Ecosystem (CCE) over the course of the previous 150 years. Using data from the Natural Resource Conservation Service's SNOTEL sites and snow course surveys, we examined the spatial and temporal variation in snowpack in the region. SNOTEL data suggest CCE snowpacks are larger and more persistent than in most regions of the Western U.S., and that water year precipitation, rather than mean temperature, is the primary control on April 1 snow water equivalent (SWE). Snow course data indicate a statistically significant downward trend in mean April 1 SWE for the period 1950-2001 but no statistically significant trend m mean May 1 SWE for the longer period 1922-2001. Further analysis reveals that variations in both Apnl 1 and May 1 mean SWE are closely tied to the Pacific Decadal Oscillation, an ENSO-like interdecadal pattern of Pacific Ocean climate variability. Despite no significant trend in mean May 1 SWE between 1922-2001, glaciers m Glacier National Park receded steadily during this period, implying changing climatic conditions crossed a threshold for glacier mass balance maintenace sometime between the Little Ice Age glacial maxima and 1922. JF - 70th Annual Western Snow Conference T3 - Proceedings of the 70th Annual Western Snow Conference PB - Western Snow Conference CY - Granby, Colorado UR - sites/westernsnowconference.org/PDFs/2002Selkowitz.pdf ER -