Spatial Precipitation Patterns in Complex Terrain Using Snow 	
	and Streamflow Observations:  Case Study of the Southern Sierra 
	Nevada, California

Jessica Lundquist(1), Brian Henn(1) and Mimi Hughes(2)
1) Civil and Environmental Engineering, University of Washington
2) CIRES, University of Colorado, Boulder

Precipitation in mountain watersheds is difficult to measure accurately over large areas 
due to its spatial variability, which is not captured well by the sparse network of gauges 
located at high altitudes. Therefore, predictions which rely on mountain basin-average 
precipitation, such as flood and water supply volume forecasts, often have large 
uncertainty.  This has led to difficulty with hydroclimate modeling and predictions in 
mountain watersheds.  However, other point observations are made more reliably in these 
areas, including snow and streamflow measurements. Here we examine patterns and causes of 
interannual variability and long-term trends in snow and streamflow in the Sierra Nevada, 
California, demonstrating how conventional precipitation gage-based methodologies have 
missed some of the patterns and dynamics most critical society, and how high-resolution 
numerical weather modeling, combined with snow and streamflow observations provides a more 
promising alternative.