Officials say the abnormally dry, warm conditions from spring and summer led to a low water supply, reducing hydropower generation.

The United States Energy Information Administration predicted hydropower generation dropped 19 percent from 2022 levels in the Northwest, Colorado, Idaho, Montana, northern Nevada, Oregon, Utah, Washington and Wyoming. The Columbia River Basin has experienced severe drought conditions since June, which will limit future water supply and — subsequently — hydropower.

Moisture from last fall and winter provided ample water supply in the region for the summer, illustrated by levels being above average in April. This quickly simmered off when temperatures soared in May and resulted in rapid snow melt, significantly reducing water supply.

California generated more hydropower than expected as record-breaking precipitation washed across the lower West Coast, filling reservoirs and layering snow in the Sierra Nevada mountains. The state had 94 percent more hydropower generation than the previous year, according to the administration.

Officials forecast that weather events reduced hydropower generation nationwide by 6 percent this year.

In June, the National Oceanic and Atmospheric Administration issued an El Niño advisory, indicating another factor that influences hydropower generation. The climatic condition is a deviation from normal wind patterns on the Pacific Ocean, which leads to dryer, warmer conditions in the northern U.S. and Canada, while conditions become wetter in the southern U.S.