Electricity shortages and blackouts are increasingly possible for the American West this summer, as an electrical operator warns of “out-of-the-ordinary” conditions.

A prolonged drought, supply-chain constraints, and other threats have led the North American Electric Reliability Corporation (NERC), an international regulatory body, to conclude that several regions in the western U.S. and Canada are at risk of severe energy shortfalls this summer.

“Industry prepares its equipment and operators for challenging summer conditions,” Mark Olson, manager of reliability assessments at NERC, said in a statement. “Persistent, extreme drought and its accompanying weather patterns, however, are out-of-the-ordinary and tend to create extra stresses on electricity supply and demand.”

The western half of North America is currently mired in the worst megadrought the continent has seen in hundreds of years, partly fueled by climate change. Drought conditions combined with high summer temperatures are expected to lead to instances of extreme heat in states such as Texas.

Extreme heat would contribute to higher-than-average peak power demands over the summer, according to NERC, which could strain energy systems already stressed by scarce fuel and other resources.

NERC notes that construction and repair projects for transmission lines have been delayed by supply-chain constraints. And for some power plants, such as coal plants, slow fuel deliveries make it less likely that infrastructure will be able to meet higher peak demand during the summer. Alternative hydroelectric power suppliers, which generate more than 7% of the country’s electricity, are also likely to have lower energy output this summer due to a below-normal snowpack this year.

Other factors, including the possibility of cybersecurity threats from Russian disruptors and an active summer and fall wildfire season, could lead to an even higher risk of blackouts, according to NERC.

Meanwhile, wildfire season in the American West appears to have begun early, with several large fires already rampaging through Texas and New Mexico. The impact of the 2022 wildfire season is expected to be “above normal,” according to an analysis by weather forecaster AccuWeather, and should the season stretch into fall, as NERC predicts, it could threaten the reliability of bulk power systems.

“Grid operators in affected areas will need all available tools to keep the system in balance this summer,” Olson said. The report cited some important improvements that have been made over the past year to critical transmission infrastructure, such as Texas’ ERCOT grid, which could help avoid catastrophic energy shortfalls, but warns regulators and utilities to remain vigilant over their electricity capacity and how external conditions play out.

“Over the longer term,” Olson said, “system planners and resource adequacy stakeholders need to keep potentially abnormal weather conditions like these in mind so that we continue to have a reliable and resilient bulk power system.”