Tornado Kills 3 in Texas as State Prepares for a Widespread Heat Wave

A storm system that swept through Texas on Thursday evening killed three people and injured dozens of others, an official said, as the state braced for a weekend of brutal heat.

The three deaths and more than 75 injuries happened in Perryton, a city where a mobile home park took a direct hit from a tornado, the local fire chief, Paul Dutcher, told NBC News. He told the station ABC7 Amarillo that firefighters were still rescuing people from the rubble as of 6 p.m.

Officials in Perryton, about 115 miles northeast of Amarillo in the state’s Panhandle, could not immediately be reached for comment.

About 50 to 75 patients were treated at the Ochiltree General Hospital in the city, Kelly Judice, the hospital’s administrator, said by phone. Their injuries ranged from cuts to traumas, she added, and 10 patients with life-threatening injuries were sent to larger facilities in Amarillo.

Videos and photographs posted to social media from the area by a CBS News journalist appeared to show flattened buildings, flooding and damaged vehicles.

Tornado warnings and watches were in effect Thursday evening for dozens of counties across Oklahoma and Texas, according to the National Weather Service.

The tornado that hit Perryton was part of a larger storm system moving through the area. The heat contributed to the storm by destabilizing the atmosphere, said Trent Hoffeditz, a meteorologist with the Weather Service office in Amarillo.

Millions of people across Texas are bracing for widespread heat that officials have said will last for days and raise the risk of wildfires and heat-related illnesses. Some daily temperature records may fall in Texas and Louisiana, including in Houston and New Orleans, the Weather Service said on Thursday.

Heat advisories were in effect on Thursday night for more than 25 million people Americans, mostly in Texas. More than 10 million others, mostly in Louisiana, were under an excessive heat watch. Some of the advisories were scheduled to remain in effect through Saturday night.

The heat index measures how hot it feels outside, accounting for temperature and humidity. A heat advisory usually indicates that the maximum index temperature is expected to be 100 degrees or higher for at least two days. An excessive heat watch indicates that the index could rise to 105 degrees or more.

Parts of Texas, including the Dallas-Fort Worth area, were expected to see heat index readings of 105 to 112 degrees Fahrenheit on Friday or Saturday, the Weather Service said in one advisory. An index of up to 119 degrees was possible in some southern countries.

Weather that hot can pose health risks for people who spend extended time outdoors or without air conditioning. Across Texas, the Salvation Army has been opening several cooling stations where people can escape from punishing heat.

It’s not unusual for officials in Texas to issue heat advisories around this time of year, said Monte Oaks, a meteorologist at the Weather Service’s San Antonio office. They typically do so when high temperatures combine with other factors, including high humidity and westerly winds that blow hot air from high-altitude deserts, he added.

In this case, Mr. Oaks said, the humidity is high because Texas had a wetter and stormier spring than usual. That has left parts of the state looking lusher than they normally do in June, he said. But it also means that the hot ground is “cooking a lot of the moisture” and releasing it into the air.

Electricity demand is expected to rise in the state later this week because of the hot weather, the Electric Reliability Council of Texas, which manages about 90 percent of the state’s electricity load, said in a statement on Wednesday. But there is enough supply to meet the demand, the company added, and it does not expect an “energy emergency.”

Global warming is making dangerously hot weather more common, and more extreme, on every continent.

In Perryton on Thursday, the Texas Department of Public Safety was responding to assist with traffic control and other needs of city and county officials, Cindy Barkley, a spokeswoman for the department, said by phone. The Ochiltree County Sheriff’s Office said it could not provide information about the extent of the damage, or whether anyone had been injured.

Barry Nusz, a storm chaser based in Amarillo, Texas, said he was about 10 miles east of Perryton as the tornado was approaching.

“It became obvious it was going to tornado and it just turned from a bowl into a big tornado that planted on to the ground,” Mr. Nusz said.

“But it quickly wrapped in rain,” he added. “We lost sight of it.”

Jesus Jiménez contributed reporting.