Widespread heat across the US West is causing the snowpack to melt at a record-breaking pace, risking water shortages and an early start to wildfire season.

Parts of the region spanning the West Coast to the lower Mountain West have less than half of the normal amount of snow typical at this time of year, the US National Integrated Drought Information System said in a statement. Some have nothing. Only parts of southern Oregon and a few places in Northern California are holding onto above-average snow pack.

The snowpack is vital to the region, which for more than 20 years has struggled with drought, leaving states struggling to maintain water supplies and contributing to wildfires. The lack of spring runoff also depletes hydroelectric capacity, a key power source for the West.

Though most areas received near-to-above-normal snow in winter, the quick melt caused much of it to change from solid to vapor, which has robbed rivers, streams and reservoirs of runoff needed to replenish water supplies.

“Snow melt this time of year is common, but such rapid melt rates are not normal,” the agency said. “Some stations in Nevada, Colorado, Utah and New Mexico saw record early melt-out.”

Unlike the east, the western US gets most of its water through the winter months and depends on snowpack high in the mountains melting slowly through the spring and early summer to fill reservoirs and rivers. The water is then used for drinking and agriculture across through the summer and fall. 

Arizona and New Mexico are often saved by their summer monsoon season, which starts in late June and July. Forecasters have been expecting a near-normal rainfall for those states.

The forecast through May 25 to 29 calls for continued high temperatures, the US Climate Prediction Center said. Just over half of the land in 11 western states is in drought, according to the US Drought Monitor. 

This article was generated from an automated news agency feed without modifications to text.