Extreme Heat and More Storms Threaten an Already Battered Oklahoma

Battered by severe storms that killed at least two people and left thousands without electricity, Oklahoma faced relentless heat and more severe storms on Wednesday as crews worked furiously to restore power in the hard-hit northeast part of the state.

Ambulance crews in the Tulsa region were struggling to keep up with calls related to the weekend storms and power disruptions, according to Adam Paluka, a spokesman for the Emergency Medical Services Authority in Tulsa.

“We had our highest-volume day ever, in our history,” Mr. Paluka said. “This chaos is our reality right now.” Emergency crews responded to 487 calls, compared with the average of 335 for a Tuesday in June, he said, with many of the calls linked to heat exhaustion or to people falling ill because they had no power for medical equipment in their homes.

With summer only just beginning, a heat dome has stalled over much of Oklahoma and Texas and is threatening to linger until the Fourth of July holiday, straining emergency resources and the power grid as demand for air-conditioning surges.

In Texas, officials issued an excessive heat warning for the Dallas-Fort Worth region and asked residents in the rest of the state to conserve electricity for fear that the power grid could buckle amid repeated triple-digit temperatures. In Oklahoma, where thousands remained without power, officials were pleading with people to spend the hottest part of the day in cooling centers.

The heat dome is the result of a high-pressure ridge in the atmosphere, the kind of conditions typically responsible for lengthy heat waves.

“In terms of temperatures, there is really no end in sight for the excessive heat that has plagued particularly south and western Texas/southeastern New Mexico,” forecasters with the Weather Prediction Center said.

On Tuesday a U.S. Postal Service carrier in Dallas collapsed during his route and later died, as temperatures surpassed 100 degrees. The medical examiner’s office said it would take time before it could determine whether excessive heat played a role in the man’s death.

Some residents in Tulsa said they were dreading the hot and stormy days ahead, which felt unusual for this time of year. Peka Jackson, 24, said that power in her apartment was restored Tuesday night and that she was “praying” that she would not go without it again. Ms. Jackson was relieved to see crews clearing fallen trees and other debris on her street Wednesday afternoon after the weekend storms.

“What can we do? What we did last time, use candles, flashlights, praying, we do a lot of praying,” she said. “You try to stay cool with a fan or anything you have.”

Storms, possibly with hail, were expected to continue battering parts of Oklahoma on Wednesday and over the next few days. But officials were more worried about the relentless heat, which was expected to hit triple digits by the weekend.

Highway and utility crews were racing to restore power lines and repair the substantial damage done by last weekend’s storms, whose hurricane-force winds knocked down trees and scattered debris that made some roads unusable. One tornado was recorded in the Oologah area.

The power grid has held in Texas. But in Oklahoma more than 100,000 customers were still without power Wednesday afternoon, mostly near Tulsa, and many of them would not have service restored for several days yet, officials said.

With the top two state officials out of the state on official business, the power to declare a state of emergency for the affected regions fell on Greg Treat, the president pro tem of the Senate. The order, which will remain in effect for 30 days, allows for the state to relax laws and regulations to bring aid faster to areas ravaged by the storm and by rising temperatures.

At least two people died as a result of the storms, in Creek County and in McCurtain County, according to medical examiners’ records.

But even some residents closer to Oklahoma City, 100 miles southwest of Tulsa, were affected by the extreme weather. Anne Harp, of Norman, said her home lost power on Sunday during the storm, and stayed off through Tuesday.

Ms. Harp said her family drove to find respite in air-conditioning in areas of town that did not lose power and only returned when temperatures dipped after sunset. “We had an emergency kit with battery fans for sleeping overnight,” Ms. Harp said. “But we had to clear out the refrigerator and the freezer. They were a complete loss.”

The National Weather Service in Oklahoma said on Wednesday that more perilous storms and possible hail were on the way as a line of storms moved in from Kansas. “As this line moves through northern and central Oklahoma,” the agency said on Twitter, “large hail and 60-80 m.p.h. winds could accompany the strongest storms.”

Extreme heat eased slightly in Tulsa on Wednesday, to a more normal high of 90 degrees, with nighttime lows in the 70s. A heat advisory remained in effect for the region because the combination of heat and humidity was expected to create dangerous conditions for people without electricity, Weather Service forecasters in Tulsa warned.

The worst of the heat was shifting on Wednesday and Thursday to western and southern Texas, as well as to portions of New Mexico, where high temperatures were expected to spike into the triple digits, threatening to break daily records in places like Abilene, Austin, Odessa and San Angelo in Texas.

Weather forecasters were also watching the Oklahoma and Texas panhandles for the possibility of more severe thunderstorms. “Those storms could produce hail the size of baseballs,” said Forrest Mitchell, a forecaster with the service.

Over the next few days, temperatures could surpass the 100-degree mark, especially in southern Oklahoma, Mr. Mitchell said. On Sunday, Wichita Falls, Texas, could reach 107 degrees.

Ben Fenwick contributed reporting from Oklahoma City.