Mayor: Actor Jeremy Renner was aiding stranded car when hurt

 Actor Jeremy Renner was assisting a stranded motorist when he was injured over the weekend in a snow-plow accident in the mountains on the edge of Reno, according to the city's mayor.

Reno Mayor Hillary Schieve said the 51-year-old "Avengers" star was trying to help a stranded car outside his home on the side of a snowy mountain on New Year's Day when he was run over by his own vehicle. The accident left Renner in critical but stable condition with chest and orthopedic injuries.

"He was helping someone stranded in the snow," Schieve told the Reno Gazette-Journal Monday night. She said she and the actor are friends and that she was called about the accident shortly after it happened Sunday morning near the Mt. Rose Highway that connects Reno to Lake Tahoe.

"He is always helping others," she told the newspaper.

The Washoe County sheriff's office said in a statement Sunday that deputies responded to a report of a traumatic injury in the area of the Mt. Rose Highway at about 9 a.m. Sunday before Renner was flown by helicopter to a local hospital. A powerful winter storm dumped more than 2 feet (0.6 meters) of snow on the area Saturday night into Sunday morning.

The sheriff's office said at the time Renner was the "only involved party in the incident" and that the office's major accident investigation team was "looking into the circumstances of the incident."

During a press conference on Tuesday, Washoe County Sheriff Darin Balaam said that they did not believe there was any foul play involved in the incident. 

"At this point in the investigation ... we believe this is a tragic accident," the sheriff said. "He was being a great neighbor and he was plowing those roads for his neighbors."

Balaam said Renner had used his Pistenbully snow groomer, a 7-ton vehicle he owns, to tow another personal vehicle that had become snowbound on a private road he shares with neighbors.

"After successfully towing his personal vehicle from its stuck location, Mr. Renner got out of his (snowcat) to speak to his family member," Balaam said. "The Pistenbully started to roll. In an effort to stop (it), Mr. Renner attempts to climb back into the driver's seat. It's at this point that Mr. Renner is run over."

The sheriff said the snowcat was impounded and is being examined by investigators "for any mechanical failure and why it started to roll."

Balaam said Tuesday that it took first responders from Reno more than 30 minutes to traverse the several miles of snowy road to reach Renner on the private road off the highway.

As many as 20 vehicles had been abandoned on the roadway while 3 feet of fresh snow fell overnight, slowing the fire engine and ambulance response.

A publicist for Renner said in a statement Monday that he suffered blunt chest trauma and orthopedic injuries and remained in critical but stable condition in an intensive care unit following surgery at a Reno hospital.

Renner took to Instagram on Tuesday to provide a brief update to his fans, thanking all for their kind words and saying he's "too messed up now to type."

Renner plays Hawkeye, a sharp-shooting member of the superhero Avengers squad in Marvel's sprawling movie and television universe.

He is a two-time acting Oscar nominee, scoring back-to-back nods for "The Hurt Locker" and "The Town." Renner's portrayal of a bomb disposal specialist in Iraq in 2009′s "The Hurt Locker" helped turn him into a household name.

"The Avengers" in 2012 cemented him as part of Marvel's grand storytelling ambitions, with his character appearing in several sequels and getting its own Disney+ series, "Hawkeye."