Declines in Snow Water Equivalent in the Pacific Northwest and Their Climatic Causes

Observations of snow water equivalent (SWE) in the Pacific Northwest are examined and compared with variability and trends in temperature and precipitation at nearby climate stations. At most locations, substantial de-clines in SWE have occurred over the past 50 years. Largest percentage losses have occurred at lower elevations (below 1000m), a pattern that is consistent with observed increases in temperature during winter and early spring. In many locations the reductions in SWE occurred in spite of likely increases in precipitation.