More than 4 million people were without power on Friday morning after the enormous ring of wind and rain known as Hurricane Helene made landfall in Florida and moved north.

It is the latest storm to show utility companies’ increasing vulnerability to extreme weather events that are becoming more common and more intense under climate change.

“There are a lot of different signs of climate-related weather risks to infrastructure,” said Catie Hausman, a professor of public policy at the University of Michigan. Those risks include hurricanes and flooding, wildfires, heat waves and increased tornado risks or cold snaps in regions less used to them.

Extreme weather has increasingly strained the grid, and it is the No. 1 cause of major power outages in the United States. In some areas of the country, the risk of hurricane-induced power outages could become 50 percent higher in the coming decades as such storms get stronger.