By Jon Herskovitz
AUSTIN, Texas (Reuters) - A cluster of late-winter prairie fires in the Texas Panhandle has killed four people, including three ranch hands racing to herd livestock to safety, while scorching hundreds of thousands of acres of grasslands, officials said on Tuesday.
Wildfires stoked by high winds and tinder-dry vegetation also raged across Colorado, Oklahoma and Kansas, prompting thousands of evacuations and destroying numerous structures. One motorist, reported to be a truck driver, died in southern Kansas on Monday night from smoke inhalation, authorities said.
NBC News reported a sixth fire-related fatality, a woman in Harper County, Oklahoma, who suffered a heart attack while trying to move cattle from harm's way. Oklahoma Governor Mary Fallin declared an emergency in 22 counties hit by wildfires in her state.
The highest death toll was in Texas, where a woman and two men died on Monday in Gray County. One victim was overcome by smoke and two died from burns, said County Judge Richard Peet.
"They were trying to move cattle away from the oncoming fire," he said in a telephone interview.
A fourth person was killed in nearby Hemphill County, but the circumstances were not immediately available, said Phillip Truitt, incident commander with the Texas A&M Forest Service.
He said one of the blazes had neared the Pantex Plant nuclear weapons facility, but the advancing flames were suppressed.
"The fire line next to Pantex is out cold, and we don't expect the fire to pose any threat to it," he said.
The largest conflagration in Texas, dubbed the Perryton fire, spread rapidly on Tuesday to blacken nearly 300,000 acres (121,000 hectares) in the panhandle region and was 50 percent contained, authorities said. That fire destroyed two houses.
Wildfires in northwestern Oklahoma prompted evacuations of multiple towns, according to state forestry officials, who said more than 10,000 acres (4,000 hectares) have burned.
At least 10,000 residents in central Kansas were asked to evacuate their homes due to a wildfire in Reno County, where about 230 responders were on the scene, the county's emergency management agency said.
More than 650,000 acres (263,000 hectares) have burned in Kansas, but the fire threat subsided on Tuesday with just eight counties reporting active blazes, according to the state's emergency management agency.
Firefighters battling a 30,000-acre (12,000-hectare) grassland fire in northeastern Colorado extended containment lines to 80 percent of the blaze's perimeter on Tuesday, but five homes, 15 outbuildings and well over 200 head of livestock were lost in the flames, said Laurie Clemons, a spokeswoman for Phillips County.
(Reporting by Jon Herskovitz; Additional reporting by Heide Brandes in Oklahoma City, Keith Coffman in Denver, Jim Forsyth in San Antonio, Kevin Murphy in Kansas City and Dan Whitcomb in Los Angeles; Editing by James Dalgleish and Bill Rigby)