Heavy rain gave the Chicago area a break Thursday morning, but other parts of the nation's midsection continued to bake in the deadly heat wave that has killed dozens over the past few days.
There have been six heat-related deaths in the Houston area this year, according to officials with the Harris County medical examiner's office.
A record for consecutive days with 100-degree temperatures was set in Austin, Texas. Wednesday marked the 21st consecutive day with temperatures above 100, shattering the former record of 19 days set in 1925.
Fifty thousand people lost power in Chicagoland as torrential downpours closed down parts of major freeways and a nuclear power plant had to suspend operations. Airports reported two-hour delays and Northwestern University shut down its Evanston campus.
The record-setting heat killed four people in the Chicago area Wednesday, bringing the total number of deaths to 19 this year, a Cook County medical examiner's spokeswoman said.
Authorities warned that the elderly are particularly at risk as they often try to save energy by not using their air conditioners.
"Seniors are often thrifty and want to save on air conditioner bills," said Brian Quinn, a Missouri Department of Health spokesman. "So they turn their air conditioner off and rely on fans."
Residents living in the affected areas were encouraged to drink lots of water and avoid strenuous activity.
Thunderstorms were forecast for the region Thursday, offering the potential for a brief respite, although temperatures were still expected to be in the 90s.
A professional football player was one of the casualties of the weather. Korey Stringer, 27, a 335-pound star tackle for the Minnesota Vikings, died of complications from heat stroke Wednesday, a day after collapsing at his Minnesota training camp.
Missouri had already recorded its 13th victim of heat this summer when a 79-year-old man was found dead over the weekend in his Raytown house, where temperatures had reached 98 degrees inside.
And the Milwaukee County medical examiner's office listed heat as a possible factor in the death of a 56-year-old man Monday, a week after a heat wave claimed the lives of four other city residents.
Hot St. Louis residents who can't afford fans or air conditioners have flocked to the New Life Evangelistic Center. The group, which advocates for the poor, has distributed more than 100 free fans and about 60 air conditioners this summer.
In Kansas, some 498 fans have been given to needy families, up from 350 during all of last year, said Tina Labellarte, chief executive officer of the Kansas Capital Area Chapter of the American Red Cross, which serves Topeka and a seven-country region in northeast Kansas.
"We find that more people are trying to keep utility costs down because they're still paying off high bills from the winter heating season," Labellarte said.
The Associated Press contributed to this report