Tornadoes Kill at Least 4 Across the South

States across the South were assessing storm damage on Friday after a series of tornadoes swept across the region, leaving at least four people dead, including three in Texas, the authorities said.

Three people were killed and more than 75 others were injured in Perryton, a city in the Texas Panhandle where a mobile home park took a direct hit from a tornado, the fire chief, Paul Dutcher, told NBC News. He told CNN that one person died in the trailer park and two others died downtown, and that one person was missing. About 200 homes and the town firehouse were destroyed, and infrared-equipped drones were surveying the damage, he said.

Officials in Perryton, about 115 miles northeast of Amarillo, Texas, could not immediately be reached for comment. The Perryton Fire Department said on Facebook late Thursday that the fire station “took a direct hit,” but that its trucks and ambulances were still operable.

“We have a lot of work to do in the days ahead to heal our community!” it said.

About 50 to 75 patients were treated at Ochiltree General Hospital in Perryton, Kelly Judice, the hospital’s administrator, said by telephone. 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. The National Weather Service said a tornado had been confirmed north of Perryton.

Gov. Greg Abbott of Texas said he was deploying emergency response teams to assist residents in Perryton.

“We remain ready to quickly provide any additional resources needed,” he said.

Another person was killed in the Florida Panhandle on Thursday night when at least one confirmed tornado struck Escambia County, knocking a tree onto a home, county officials said in a statement.

More than 640,000 customers across the South were without power on Friday, according to the site poweroutage.us, which aggregates data from utilities across the United States. About 212,000 customers were without power in Texas, with most of the outages there centered in the northeastern corner of the state. Millions of others in Texas were bracing for widespread heat that officials said would last for days and raise the risk of wildfires and heat-related illnesses.

Meteorologists said there was a slight risk of severe thunderstorms on Friday from southeastern Colorado to the Texas Panhandle, where hail, damaging wind gusts and tornadoes were again possible.

Some daily temperature records may fall in Texas and Louisiana, including in Houston and New Orleans, the Weather Service said. Heat advisories were in effect on Friday for more than 30 million people, mostly in Texas. More than 15 million others across Texas and Louisiana were under excessive heat warnings. Some of the advisories and watches were scheduled to remain in effect through Saturday night.

Meteorologists describe heat waves using a heat index, which accounts for both temperature and humidity to measure how hot it feels outside. 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 tends to mean that the index could rise to 105 degrees or more.

Heat index readings up to 115 degrees were expected in parts of Texas on Friday or Saturday, the Weather Service said in one advisory.

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.

Climate change is making dangerously hot weather more common, and more extreme, on every continent. In Texas and neighboring Mexico, it is making excessive heat forecast over the next few days at least five times as likely, according to an analysis on Wednesday by Climate Central, a nonprofit research collaboration of scientists and journalists.

Barry Nusz, a storm chaser based in Amarillo, said he was about 10 miles east of Perryton on Thursday afternoon 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.”

Johnny Diaz, Jesus Jiménez, Derrick Bryson Taylor and Remy Tumin contributed reporting.