(The Hill) — Much of the U.S. power grid is at an increased risk of failure during major storms or prolonged cold snaps this winter, a top energy regulator warned on Wednesday.

The North American Electric Reliability Corporation said that much of the central and eastern U.S. is at an “elevated” risk of power failure. The risk encapsulates every region east of the Rocky Mountains, except for the Southeast and Upstate New York.

While the regulator said grids can handle normal winter loads, “any prolonged, wide-area cold snaps will be challenging” due to the extra strain that puts on power generators.

“Extreme cold weather events can cause electricity demand to deviate significantly from historical forecasts,” said Mark Olson, NERC’s manager of reliability assessments, in a statement. “The growth of intermittent resources, like solar generation, on the distribution system significantly increases load forecasting complexity and uncertainty.”

“Once again, we strongly recommend that operators take the necessary steps to prepare for winter,” he added.

Last December, winter storm Elliott left hundreds of thousands without power throughout the Southeast and New England after prolonged extreme temperatures stressed power infrastructure. 

More than 60 percent of the U.S. population was placed under a winter storm advisory for that storm, with power outages impacting people up and down the East Coast.

A report from the Federal Energy Regulation Commission last month found that about 18 percent of the entire country’s electric generation failed during the storm.

A similar “bomb cyclone” struck Texas in 2021, almost completely shutting down the state’s energy grid. Over 4.5 million people went without power, some for days, and a deregulated energy market shot up prices for consumers, sparking calls for radical changes.

Winter weather is forecasted to be more extreme this year due to El Niño patterns in the Pacific Ocean, which usually cause increased snow fall and colder temperatures.

While much of the central and eastern U.S. is projected to get a colder, snowier winter — especially around the Mid-Atlantic — parts of New England and the Great Lakes are forecast for less snow.

To prepare, the regulator urged local utility managers to properly plan and practice what to do if power demands become unsustainable, including how to manage load-shedding through rolling brownouts.

In response, industry group North American Energy Standards Board announced it will develop new standards language to assist utility operators in creating preparations for winter weather.