PHILADELPHIA — Americans dipped into the water, went to the movies, and rode the subway just to be in air conditioning Saturday for relief from unrelenting heat that has killed 30 people across half the country.
The heat sent temperatures soaring over 100 degrees in several cities, including a record 105 in Washington, 106 in St. Louis, and 104 in Indianapolis. It buckled highways and derailed a Washington-area train even as another round of summer storms threatened.
At least 30 deaths were blamed on the heat, including nine in Maryland and 10 in Chicago, mostly among the elderly.
Three elderly people found dead in their houses in Ohio had heart disease and died amid high temperatures in homes lacking power because of recent outages, officials said. Heat also was cited as a factor in three deaths in Wisconsin, two in Tennessee, and three in Pennsylvania.
Officials said the heat caused highways to buckle in Illinois and Wisconsin.
In Maryland, investigators said heat probably caused rails to kink, leading to partial derailment of a train in Prince George's County on Friday afternoon. No one was injured, and 55 passengers were safely removed.
Transit officials in Washington imposed a 35-mph speed limit on all trains that travel above ground — 20 mph slower than they typically travel — after the derailment because of a "heat kink," the expansion of a metal track because of the heat.
Thousands of mid-Atlantic residents remained without power more than a week after deadly summer storms and extreme heat struck the area. They included 120,000 in West Virginia and about 8,000 in the suburbs around Baltimore and the District of Columbia.
In Ohio, temperatures reached at least 100 degrees in Toledo, Columbus, Hamilton, Akron, and Cincinnati.
The sweltering temperatures could not stop two big events in the Buckeye State.
Country music fans dumped buckets of water over their heads and sat on bags of ice at the annual Country Concert in Fort Loramie as they waited for headliners Blake Shelton and Luke Bryan to close out the three-day festival.
In Dayton, the turnout at the annual air show was a bit smaller despite a Saturday appearance by the U.S. Navy's Blue Angels, said show general manager Brenda Kerfoot.
At the air show, at least 16 people had been taken to hospitals for heat-related illness by late afternoon as temperatures reached 102 degrees, Ms. Kerfoot said.
About 200 medical workers at the airfield were kept busy during the day, she said.
Gov. John Kasich and other state officials urged people to make sure their neighbors and relatives were staying cool during the heat wave.
They encouraged people without air conditioning to go to cooling centers and said those suffering from the heat could go to fire stations to find out where they can seek relief.
Many were still without power after storms that hit Ohio in the past week. American Electric Power-Ohio said Saturday morning that about 66,000 customers remained without power, mostly in the central and southwest parts of the state. The utility said it hoped to restore electricity to nearly all its customers by the end of the day.
In northwest Ohio, nearly 3,000 Toledo Edison customers remained without power Saturday evening, two days after a severe thunderstorm felled trees and snapped utility poles in the area.
Temperatures soared above 90 for a record 10th straight day at Toledo Express Airport.
The high temperature of 100 degrees at the airport marked the third time in 10 days that the mercury reached triple digits in Toledo, although it was three degrees short of the local record set during a 1988 heat wave. A temperature of 102 was recorded at The Blade building.
Records were set Saturday in Defiance and Lima, Ohio, and in Hillsdale, Mich. Defiance's 103 and Lima's 101 topped 100-degree records set in 1988 and 1936, respectively, and Hillsdale's 102 beat a 98-degree record from 1988. Also reaching triple digits were Toledo Executive Airport and Adrian, both at 102, and Findlay and Monroe, both at 100.
But relief was on the way, none too soon for utility customers in Springfield and Sylvania townships and Toledo, where damage from Thursday's storm was most extensive.
A cool front forecast to pass through the region overnight was expected to lower temperatures to no more than the upper 80s today and the low-to-mid 80s for the next three to four days, according to the National Weather Service.
Thunderstorms were possible during the frontal passage, and sunny days were predicted to prevail through the week afterward, with another warmup by next weekend.
Toledo Edison spokesman Doug Colafella said all power was expected to be restored overnight in Springfield Township, by noon today in Sylvania Township, and by 11 p.m. today in Toledo.
The heat sent temperatures soaring in more than 20 states — to 105 in Louisville, 101 in Philadelphia, and 95 in New York; besides in Washington, a record of 104 was set in Sioux Falls, S.D., and a record of 102 was set in Baltimore.
Meteorologists said the recent hot streak, although not unprecedented, was unusual because of how early in the summer it struck and because of its duration. The prolonged heat has been the result of a high pressure system that has set up over the central and Eastern parts of the country, said Katie Garrett, a meteorologist with the National Weather Service.