Very impressive fire behavior in Alaska

Douglas Burts, who posted this video shot at the Tetlin Juction Fire August 16, 2013, called it Alaska Firenado. While I’m not sure that there is an official definition of the term, there is definitely rotation in this smoke column, and it appears to be more than just horizontal roll vortices. Whatever we call it, this fire behavior is very impressive.

Wildfire briefing, August 14, 2013

Firefighter deaths resulting in changes

Rocky Barker of the Idaho Statesman has written an interesting article about how the death of 20-year old Anne Veseth of Moscow, Idaho a year ago this week has changed procedures in some wildfire organizations. She was killed on the Steep Corner Fire, 56 miles northeast of Orofino, Idaho August 12, 2012. The fire was on private property and was being managed by the Clearwater‐Potlatch Timber Protective Association (CPTPA). Ms. Veseth, in her second season working as a firefighter for the USFS, was killed when she was struck by a falling 150-foot tall fire-weakened green cedar tree. The tree fell on its own and was 13 inches in diameter where it struck her. The official report about the fire found no fault, and included this statement:

This tragedy resulted from the chance alignment of certain conditions: an emergency response to control a wildland fire, which required the presence of firefighters in an area where fire‐weakened trees could fall on their own with little or no warning.

The day before the fatality, a Hotshot crew and an engine crew refused to work on the fire after they observed serious safety issues.

Plane crash starts small fire

The crash of a small plane in northern California killed the two people on board and started a vegetation fire that burned 15 acres before firefighters stopped the spread. Federal Aviation Administration spokesman Ian Gregor says the plane crashed at about 11:30 a.m. Tuesday about five miles east of Chico in Butte County.

Large firewhirl photographed

A large fire whirl, sometimes called a fire tornado, was photographed on the Summit (name changed to Rockport) Fire north of Park City Utah on August 13. A new term has been introduced. Some people are calling this a “firenado”, which could be a takeoff from the “Sharknado” movie.

 

Revisiting the Australian fire tornado

Chris Tangey Fire Tornado
Screen grab from the Chris Tangey Fire Tornado video

Kelly sent us this screen grab that was taken from the 40-minute video that Chris Tangey shot of the fire tornado he discovered when he was scouting locations near Curtin Springs station in Australia. It reminded me of how incredible the images are. If you have not seen the video, check it out here.

The phenomenon stayed in about the same place and lasted for 40 minutes.

 

Thanks go out to Kelly

A fire whirl in the lab

We have written a number of times about fire whirls and fire tornadoes observed in wildfires. They can be very impressive and very dangerous…. except when they are created in a laboratory as in the video below. A tip for viewers… after about a minute and a half, there is very little change in the images until the fire dies out near the end.

The University of Maryland’s Department of Fire Protection Engineering created this fire whirl using heptane as the fuel in a compartment with four specially-located openings which induced a “whirl” when the exhaust hood was turned on. It was photographed at 300 frames per second. The University’s web site has more information, including a photo of people roasting marshmallows in the flames.

 

Thanks go out to Daniel

Documented fire tornado

Fire Tornado path, Australia
Fire Tornado path, Australia. Credit: research led by Rick McRae

We have previously written about events described as “fire tornadoes”, but research led by Rick McRae in Australia has us convinced that those should be more accurately called fire whirls, not tornadoes. We were never very comfortable using the term “fire tornado” for those events, but it has become common and we were not aware, until now, that a phenomenon many times more powerful existed.

Fire Tornado documentation, Australia. Credit: research led by Rick McRae
Fire tornado documentation, Australia. Credit: research led by Rick McRae

Mr. McRae documented what was unquestionably a real fire tornado that occurred near Chapman, ACT, Australia during the McIntyres Hut Fire January 18, 2003.

Researchers had speculated about the ability of a fire to produce a tornado, but this is the first documentation of the creation of a true tornado by the convection column of a large fire.

In a video interview (scroll down and view the second video) and in a paper published October, 2012 in the journal Natural Hazards, he described a fire tornado as occurring over a vegetation fire, a process now known as the phenomenon of “pyro-tornadogenesis”. Under certain conditions, a fire can cause a pyro-cumulus cloud to form, which is not in itself unusual over a large fire. If the cloud continues to build, it can generate lightning, rain, and hail, much like a conventional large thunderstorm. And large thunderstorms can sometimes propagate a tornado, which is what happened over the McIntyrres Hut Fire.

Mr. McRae’s research determined that the fire tornado was moving across the ground at 30 kph (19 mph), had horizontal winds of 250 kph (149 mph), and vertical winds of 150 kph (93 mph).

Fire tornado, broken-off trees
Aftermath of a fire tornado, showing 12-15 meter tall trees broken off 2-3 meters above the ground. From research led by Rick McRae.

Dr. Jason Sharples, also associated with the research, described the differences between a fire tornado and a fire whirl:

Tornadoes are associated with thunderstorms and as such they are anchored to a thundercloud above, and are able to sporadically lift off the ground. Fire whirls, on the other hand, are anchored to the ground and do not require the presence of a thunderstorm.

Rick McRae is a Special Risks Analyst at the ACT Emergency Services Agency.

 

Thanks go out to Chris

Better video of the Australian fire tornado

Loyal readers of Wildfire Today will remember back to September 18 when we posted a video of a fire tornado shot by Chris Tangey of Alice Springs Film and Television while he was scouting locations near Curtin Springs station in Australia. Mr. Tangey contacted us to let us know that the Channel 7 video was removed from YouTube due to copyright issues, but a better version of the video, provided by Mr. Tangey, is now available at Vimeo.

We are embedding it below. If you want the very impressive video to fill your screen, hover your mouse pointer over the video then click on the arrows at the bottom-right between “HD” and “vimeo”.

Outback fire tornadoes-Australia from chris tangey on Vimeo.

Below is a description of the video:

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“THERE’S something mean and magical about Australia’s Outback. An Alice Springs filmmaker captured both when a whirlwind of fire erupted before his eyes.

Chris Tangey of Alice Springs Film and Television was scouting locations near Curtin Springs station, about 80km from Ularu, last week when confronted by a fiery phenomenon. He had just finished his tour of the station when workers encountered difficulties with a grader. So he went to help them.

A small fire was burning in nearby bushland, so Mr Tangey decided to start filming. He caught the sight of his life. A twister touched down on the spot fire, fanning it into a furious tower of flame.

“It sounded like a jet fighter going by, yet there wasn’t a breath of wind where we were,” he told the Northern Territory News.

“You would have paid $1000 a head if you knew it was about to happen.”

The column of fire danced about the landscape for about 40 minutes, he said, as he and the station workers stood transfixed. There was talk of making a quick getaway, Mr Tangey said. But everyone was too hypnotised to feel scared – and he continued furiously filming.

“The bizarre thing was that it rarely moved,” he said.

“These things just stood there because there was no wind to move them … but it was flickering incredibly fast.”

Darwin weather forecaster David Matthews said small twisters were common in isolated areas. But the fiery vortex was highly unusual.

“The flames would have assisted by trying to suck in air and that could have helped generate those circular winds,” Mr Matthews said.”