California wildfires: Deadly fire tornado reaches wind speeds of more than 143mph

The Carr wildfire has so far killed six people and burned more than 126,000 acres

A 'fire tornado' that left a trail of devastation through northern California last week generated wind speeds of more than 143mph, according to investigators.

The phenomenon was captured on video as the city of Redding was ravaged by the Carr wildfire which has so far killed six people, destroyed more than 1,000 buildings and burnt through 126,000 acres.

So severe was the damage caused by the rotating column of fire and smoke on the evening of 26 July that the National Weather Service (NWS) in Sacramento said that it was equivalent in intensity to an EF-3 scale tornado.

"Preliminary reports include the collapse of high tension power line towers, uprooted trees and the complete removal of tree bark," the NWS said. "Preliminary indicators placed max wind speeds achieved by the fire whirl in excess of 143 mph."

Firefighters are still battling the eleven-day-old blaze and the latest update from the California Department of Forestry and Fire Protection (CalFire) agency shows it is only 37 per cent contained.

Roads remain blocked by downed power poles, bridges are damaged and more than 20,000 evacuees still have not been allowed to return to their homes.

The Carr wildfire is one of more than 100 burning across 13 western states, having consumed more than 1.4 million (582,000 hectares), according to the National Interagency Fire Center.

An estimated 27,000 firefighters have been deployed, with 13,000 in California alone. They have been joined by a contingent of 100 firefighters from Australia and New Zealand who are reinforcing exhausted crews in northern California, Oregon and Washington state.

"I think the biggest issue is the infrastructure damage is horrendous," said Ken Pimlott, California's top fire official.

One of the homes destroyed in the Carr wildfire belonged to Robert Tierney Jr, a member of staff at Dignity Health Mercy Medical Center in Redding.

Mr Tierney managed to grab a wedding dress and a few hampers of clothes before fleeing his neighbourhood.

"I have to come to work," the 57 year-old said. "My wife is disabled and I have to make a living and I have a terrific job and it is my pleasure to be here, so I'm just real fortunate I have a job to come to at a time like this."

Mike Mangas, spokesman for Dignity Health North State, said 67 staff and volunteers at the hospital are without permanent shelter because their homes are too damaged.

"It's been amazing," he said. "There have been people sleeping on the floor at the hospital, people sleeping at relatives', or in hotels if they can get them."

Churches have thrown open their doors and the Red Cross has turned high schools into temporary shelters.

Others have tried to help by hadning out hot dogs and hamburgers to victims on street corners, offering their spare rooms and vehicles or taking in pets and livestock.

Firefighters conduct a controlled burn to defend houses against flames from the Ranch fire (MARK RALSTON/AFP/Getty Images) (Getty)

Carla DeLauder, who fled the fire to stay with her parents 225 miles away, said her flock of chickens had been rescued from her home in Redding by people she had never met.

She said: "I mean, chickens? I didn't even consider that someone would go out to help my flock of chickens let alone rescue them."

Ms DeLauder, 57, is now waiting for confirmation that her home has power now that the roads have reopened.

"People are very tired and anxious to get home," said Red Cross spokesman Stephen Walsh. "Those who have a home to go back are frustrated they can't go home."