Hydro net generation was down more than 9% in the Western Electricity Coordinating Council, or WECC, region during the first quarter of 2014 compared to the average first-quarter net generation each year between 2009 and 2013, according to a report from SNL Energy.

The 3,145-GWh decline was largely driven by an almost 54%, or 2,273-GWh, drop in California compared to the 2009-2013 first-quarter average. The state is experiencing a severe drought, which has been forecast to continue into the summer and may expand across the Southwest.

In the first quarter of 2014, six of the nine U.S. states in the WECC region experienced declines in hydro generation compared to the average first-quarter net generation in the previous five years. Canadian hydro resources in the WECC region were not included in this analysis. California led the way in terms of both percentage point decline and net generation decline, while Wyoming came in second in terms of percentage decline, with a drop of 34%, and Washington came in second in terms of generation decline, with a drop of 761 GWh. Washington has the largest amount of operating hydroelectric capacity in the U.S. WECC region, and Wyoming has the least.

At 30,556 GWh, first-quarter hydro generation in WECC was at its lowest since 2010, when the region produced 26,449 GWh. That year, seven of the nine states in WECC reported a decrease in hydro generation compared to the first quarter of 2009. Wyoming had the largest downturn in terms of percentage, with a 54% reduction, while Washington had the largest downturn in terms of generation, producing 3,177 GWh less than in the first quarter of 2009.

Hydro generation by both hydraulic turbine and pumped storage facilities in WECC has been declining since a peak in 2011 with 45,316 GWh. In the Northwest, high temperatures in January 2012 caused significant snowmelt and runoff, and La Niña conditions drove heavy precipitation during the quarter. Net generation in the first quarter of 2012 was 25% lower than in the prior year's first quarter, and the first quarters of 2013 and 2014 brought subsequent declines of roughly 6% and 4%, respectively.