People flocked to pools, beaches and cooling centers in a swath of the Midwest and South spanning from northern Florida to the Great Lakes on Wednesday as a heat wave pushed temperatures into the 90s and beyond and may have caused the deaths of at least two people.

The National Weather Service maintained an excessive heat warning through Wednesday evening for most of Illinois, Indiana and Ohio, which have been dealing with the sticky humidity and soaring temperatures since Tuesday. And the heat advisory in place for the Midwest and South stretched all the way eastward to the South Carolina shoreline, covering an area that is home to roughly a third of the country's population.

Meteorologists warned that the high temperatures could be dangerous or deadly for some people and advised residents to stay hydrated, remain indoors if possible and take precautions if they must be outside. Driving home the point, the Milwaukee County Medical Examiner's Office tweeted Wednesday that it was investigating the deaths of an 89-year-old man and 39-year-old woman for "probable" connections to the heat.

"There are a lot of vulnerable populations exposed to this heat," University of Georgia meteorology professor Marshall Shepherd said. "I am particularly concerned about the elevated nighttime temperature. That's what kills people if they are not adequately prepared or have the appropriate resources. Hurricanes get the headlines, but heat kills more people every year in the U.S."

As temperatures soared into the 90s in downtown Indianapolis on Wednesday, Gary Lightle kneeled on the hot steps of the Indiana World War Memorial to replace some aging caulking. He wore a wide-brimmed hat and began his work day around 7 a.m. but said the heat dictates how long he stays outside.

"Yesterday it just got so miserable that we decided to quit at 3," he said.

Foreman CJ Thrasher's workday starts even earlier — around 5 a.m., he said, to beat the heat — with usually a 2 p.m. wrap-up.

Thrasher worked quickly to apply glue to the side of a stone wall on W Ohio Street. In the heat, the sealant stiffens faster than in cooler weather, he said, so the glue becomes less malleable.

"With this heat, just like that, it's done," Thrasher said, setting a small tile on an open space in the wall.

For those off the clock, Wednesday's heat inspired trips to the beach, river, pool or splash pad, launching the summer swimming season a bit earlier than usual in some northern locales. Authorities throughout the affected area encouraged people without access to air conditioning to use public cooling centers, libraries and other public places to escape from the heat and humidity.

Some areas were expected to get relief by Thursday. But the hot weather moving out could bring severe thunderstorms Wednesday to Iowa, Wisconsin and points eastward, including Michigan, according to the weather service's Storm Prediction Center. Those storms could dump large hail or spawn tornadoes or damaging straight-line winds.

Utilities sorted out many of the power outages caused by storms that swept through the Midwest early in the week, but more than 200,000 customers remained without power still as of Wednesday afternoon, according to

Joe Champion said he'd experienced intermittent outages at his home in Columbus, Ohio, since Tuesday afternoon. Champion, 38, said he spent part of Tuesday evening in his car running the air conditioning, despite soaring gas prices in the U.S.

"There was just no way I could sit in the house," he said.

Meanwhile, crews worked to restore water service Wednesday to the West Texas city of Odessa, where residents have gone without it this week amid scorching temperatures because an aging pipe broke.