#fire tornadoes

[pyro-baby]

[neopets-killed-my-wife]

Me flirting: so what's your favorite weather phenomenon?

[rjzimmerman]

The ecological upheaval of Jasper National Park

Excerpt from this story from Sierra Club:

Between July and September of 2024, 33,000 hectares (81,544 acres) of forest burned in the Athabasca Valley of Jasper National Park, a Rocky Mountain wilderness hugging Alberta’s border with British Columbia.

For its size, the Jasper Wildfire Complex was unremarkable. The park itself is 1.1 million hectares; 28,000 burned during the wildfires of 2003. In 2023, 2.2 million hectares burned across Alberta in a wildfire season ultimately claiming 12.7 million across Canada.

If the 2024 Jasper wildfire stands out, it’s for its intensity. Ignited by lightning on July 22, the wildfire promptly generated a pyrocumulonimbus (pyroCb) storm system, in which hot air rises to the upper troposphere in a rapid column of smoke, ash, embers, and water. Not only does this column produce a relative vacuum on the ground, triggering hurricane winds to fill the void, but the injection of heat and moisture into the atmosphere breeds lightning storms, igniting more fires in turn. This phenomenon also rains embers, allowing fire to leap hundreds of meters at a time.

“PyroCbs are still an area of active research,” said Mike Flannigan, BC innovation research chair in predictive services, emergency management, and fire science, based at Thompson Rivers University in Kamloops, BC. “A colleague and I wrote about a notable one in 1986. It generated lightning, new fires, rain, hail—you name it. But we wrote about it because, at that time, they were rare.”

No longer. In 2021, the number of pyroCbs reached 102 globally, a record broken in 2023 when Canada hosted 142 of them. Jasper’s was a monster, one of the most severe ever to hit the Canadian Rockies.

There was also, probably, a fire tornado in Jasper. No one was there to see it, but the signs were clear to Aaron Lawrence Jaffe, an engineering researcher with the Northern Tornadoes Project at Western University. He was on the ground in September 2024 and saw cast-iron firepits, steel garbage bins, even shipping containers that had been flung from one side of the Athabasca River to the other. He also found huge swathes of forest debarked and flattened by 110-mile winds. Snaking through the valley were the distinct paths of vortexes.

“That’s something you see in a very intense tornado,” said Jaffe.

In order to be a bona fide “tornado,” the funnel must connect both to the clouds above and the ground below, he said, which is difficult to demonstrate after the fact. But if it wasn’t a true tornado whipping through the Jasper Wildfire Complex, then it was something we don’t have a name for. If confirmed, this will be the second fire tornado ever recorded in Canada.

Like pyroCbs, fire tornadoes remain the subject of active research, so rare a phenomenon that meteorologists aren’t sure what to make of these biblical variants—a swirling vortex of oxygen, ash, and yes, fire, usually, but not always, accompanied by a pyroCb.

Natural Resources Canada is still finalizing its report on the Jasper Wildfire Complex, with informed estimates of temperature, windspeed, updraft, among other variables, but one of its more evocative findings has escaped in the form of an analogy: This fire emitted so much radiative heat, it could have burned exposed skin a kilometer away.

[weathermate]

A way to harness 'complete combustion' for good.

[mammothhorse]

OH NO!! I just heard about the fire tornadoes in San Diego! Is everyone alright!!

[thegeminisage]

why do people think of talking about the weather as the low point in a conversation tho

weather is fucking fascinating

[io9dotcom]

How to make a fire tornado using household objects (PS: please don't make a fire tornado)

By Esther Inglis-Arkell

It’s easy to make a fire tornado out of household objects. You just need some lighter fluid, a lazy susan or microwave tray, and a mesh metal garbage can. But why does the flame get so high just from a little rotation? We’ll give you a quick physics explanation.

Fire tornadoes look powerful -- and I’d advise against messing with one -- but they climb so high because the fire is actually having a tough time. It’s being deprived of oxygen. This is a rare thing for fire, because it creates the mechanism that brings more oxygen to it. It heats the air around it -- air thick with carbon dioxide -- and that heat cause the air to become less dense. Less dense air floats upwards, creating a vacuum that suck fresh air in. This is how fires keep feeding themselves more oxygen.

If there’s rotation of air around the flame, the air still gets sucked in, but it forms a kind of whirlpool around the flame. Like whirlpools in water, the air goes faster and faster the more it’s sucked towards the flame. You can see this principle at work if you spin your office chair and slowly pull your arms or legs inward, or if you twirl an object on a string and pull in the string. As it gets closer to the center, it spins faster.

Even though the air moves fast, it is not providing an efficient oxygen delivery system to the fire. It would be much more efficient just for the air to move directly in. Instead it’s forming a swirl that keeps the air circling the fire for quite some time. The fire is choked off, and elements that would have caught fire immediately in an oxygen rich environment climb higher before they get the oxygen they need to completely combust. So the flame moves upwards, and we get a dramatic fire tornado.

[Via The Naked Scientists]