A vast swath of North America from the Great Lakes to the West Coast is at risk of blackouts this summer as heat, drought, shuttered power plants and supply-chain woes strain the electric grid.

Power supplies in much of the US and part of Canada will be stretched, with demand growing again after two years of pandemic disruptions, according to an annual report. It’s among the most dire assessments yet from the North American Electric Reliability Corporation, a regulatory body that oversees grid stability.