Authors: Bryan Mood*, University of Victora & University of Saskatchewan, Bethany Coulthard, University of Nevada, Las Vegas, Dan Smith, University of Victoria
Topics: Water Resources and Hydrology, Climatology and Meteorology, Canada
Keywords: dendrochronology, dendrohydrology, snowpack, hydrology, British Columbia, paleoclimate, teleconnections
Session Type: Paper
Presentation File: No File Uploaded
Recent snow droughts have limited melt contributions to runoff during the late spring and early summer months in southwestern British Columbia (SWBC), Canada. The corresponding reduction in seasonal streamflow has led to cascading ecological impacts that draw attention to the impending consequences of climate change. Knowledge of annual winter snowfall variability within this region is largely derived from a sparse network of short-duration (≤50 years) snow survey stations. We developed two long-term April 1 snow water equivalent (SWE) records from tree-rings and supplementary teleconnection indices. Our dendrohydrological models accurately estimate April 1 SWE for coastal and continental regions of SWBC to AD 1710 and 1725, respectively. Both reconstructions contain generally synchronous step changes in the scale of annual SWE. They demonstrate annual April 1 SWE dynamics in this region are strongly associated with negative (cold) phases of the Pacific Decadal Oscillation and the El Niño-Southern Oscillation, and show that SWE in coastal settings experiences far greater year-to-year variability than in more continental locations. While the coastal SWE reconstruction illustrates eleven significant step changes in magnitude since the early 1700s, only eight step chances are identified in the proxy SWE record. Two periods, between 1804-1821 and 1887-1927, suggest that SWE coastal regions are more sensitive to minor changes in snowpack when compared to continental areas. The models provide the first high-resolution description of April 1 SWE over the past 300 years in SWBC and offer significant insights for resource policy makers and planners.