Sweltering Heatwave Seizes Much of the U.S.

U.S.|Power outages add to the misery in the Midwest as sweltering heat seizes much of the U.S.

• Aug. 12, 2021, 5:28 a.m. ET

More that 150 million people across the United States were under some form of heat alert on Thursday with baking temperatures expected in the Pacific Northwest, parts of the Plains and the South, and much the Northeast.

In the Midwest, hundreds of thousands of people were facing the prospect of confronting boiling temperatures and stifling humidity without electricity and air conditioning after blustering winds and heavy rains ripped through the Great Lakes this week. Gusts of up to 80 m.p.h. have toppled trees and power lines, causing widespread power outages in Wisconsin, Illinois and Michigan.

“Food spoilage, no air conditioning, medicine that needs to be refrigerated,” said DeWayne Smoots, a deputy chief with the c Fire Department, listing the concerns facing residents there. “How do you stay cool? Going outside is not going to help you.”

On Wednesday, Mr. Smoots and his team navigated roads strewn with uprooted trees to respond to dozens of calls across the city about downed power lines. Recovery efforts were challenged by continued severe thunderstorms throughout the region Wednesday night, with much of the state under a tornado watch.

On Thursday, temperatures could reach into the 90s in some place where the power has been out in southern Wisconsin, Illinois and Michigan.

Temperatures also threaten to break records in the Pacific Northwest on Thursday, less than two months after an extreme heat wave hit the region, leading to hundreds of deaths. Record-breaking temperatures are expected in the Northeast Thursday, too. The heat index value — which combines the air temperature with humidity to provide a number for what the air actually feels like — was forecast to reach as high as 106 in New York City, and up to 110 in Washington, D.C.

In Portland, Ore., a high of 100 was expected Thursday.

“Yes, it’s summer, but this type of heat can kill,” the National Weather Service warned on Twitter, encouraging people in areas experiencing extreme heat to avoid strenuous activity and stay hydrated.

And in California, firefighters were bracing for the continued spread of the Dixie Fire as thunderstorms threatened to form over the blaze, which has now consumed more than 500,000 acres.

Dusty winds whipped up by the storms could cause “chaotic behavior,” said Rich Thompson, a National Weather Service who has been tracking the Dixie Fire. The storms are not expected to bring rain that would help temper the fire, he said, though the exact storm conditions where the fire is spreading were difficult to predict.