Search and rescue teams look for survivors Thursday in a destroyed Dollar General in Matador, Texas. A line of severe storms produced what a meteorologist calls a rare combination of multiple tornadoes, hurricane-force winds and softball-sized hail in west Texas, killing at least four people and causing significant damage .

A line of severe storms produced what a meteorologist calls a rare combination of multiple tornadoes, hurricane-force winds and softball-sized hail in west Texas, killing at least four people, injuring nine and causing significant damage around the town of Matador, a meteorologist said Thursday.

The storms produced strong winds that swept across Texas, from the Panhandle to Houston, causing damage north of the city, weather officials said.

Gov. Greg Abbott added six counties in the region to a disaster declaration Thursday. The declaration was first issued June 16 and amended three times in response to severe weather. His statement said the declaration will help state authorities respond swiftly to devastated communities.

Storms were forming again Thursday afternoon, and National Weather Service meteorologist Alex Ferguson in Amarillo said they were possible into the night, with a chance of more large hail – up to 3 inches in diameter – and winds up to 70 mph. Severe thunderstorm warnings were issued Thursday afternoon in parts of Oklahoma and Texas, while tornado warnings were issued in parts of Texas and Colorado.

About 8 p.m. Wednesday, a supercell developed near Amarillo before striking the small town of Matador, said senior forecaster Matt Ziebell with the National Weather Service in Lubbock. He called it “certainly rare to see all at the same time – killer tornadoes, hurricane-force winds and softball-sized hail.”

The damage was concentrated on a 1-mile stretch with businesses and homes demolished along the west side of Matador, a town where “everybody knows everybody,” said Brandon Moore, Matador’s water superintendent, who is also a volunteer firefighter.

“It was supposed to move east of us, and within a five-minute timespan, it all changed and switched directions and came straight through Matador,” Moore said. “We probably had about two minutes of warning to get everybody together and get to safety. There’s a few people that didn’t make it out of the house, but we did rescue several people and they made it out all right.”

The city is receiving lots of help from people arriving from outside the community, he said.

“Everybody in the world is offering to come help, which is good,” Moore said. “We’re trying to clean up the mess now and go from there.”

The storm produced 109 mph winds in Jayton, as well as hail more than 4 inches wide, Ziebell said. The weather service reported a 97 mph wind gust – the strongest recorded at George Bush Intercontinental Airport in Houston since data collection began there in 1969. The previous record there was 82 mph during Hurricane Ike in 2008.

Much of the wind damage near Houston – downed trees and knocked down power lines and fences – happened north of the city.

The weather service sent crews to survey the damage in west Texas on Thursday and determine the strength of the tornadoes, but the team had not reported its findings as of early Thursday afternoon, according to meteorologist Robert Barritt in Lubbock.

Wednesday “was definitely a rare combination of high-end wind shear and storms of extreme instability,” Ziebell said.

The worst damage appeared to be in Matador – a town of about 570 people about 70 miles northeast of Lubbock in Motley County. Homes were damaged, buildings were flattened and power lines were snapped in half. A restaurant’s walls were all knocked down, but the booths remained standing in what was called a “jaw-dropping” scene by Derek Delgado, a spokesperson for Lubbock Fire Rescue.

“You would look on one side where we had a general merchandise store completely flattened to the ground, but across the street, there’s a house that’s still standing and the vehicles haven’t even moved from the driveway,” Delgado said by telephone.

Power outages were widespread across the sparsely populated west Texas region, with over 900 customers losing power in the Matador and Jayton areas, according to PowerOutage.us. Those areas have fewer than 2,000 people combined.

A cooling center was opened in Matador with highs expected near 90 degrees Fahrenheit.

In Harris County, which includes Houston, almost two dozen cooling centers were opened as nearly 90,000 customers remained without power. Thursday’s advisory warned the heat index could reach 109 degrees Fahrenheit.

Wednesday’s tornado outbreak came six days after a tornado left three people dead and more than 100 injured in Perryton in the northern Texas Panhandle.

Nearly 75,000 customers in Oklahoma and Louisiana remained without electricity Thursday as work crews continued to repair power lines damaged by weekend storms.

Another hailstorm pummeled concertgoers at Red Rocks Amphitheater Wednesday night in Morrison, Colorado, near Denver. Seven people were hospitalized, according to KMGH-TV. None of those taken to hospitals had life-threatening injuries, and up to 90 people were treated for injuries at the amphitheater, according to West Metro Fire Rescue.

Associated Press reporter Juan Lozano in Houston contributed to this report.