Record temperatures in Canada create dangerous clouds of fire

A cloud of fire over Washington.

NASA Earth Observatory

  • If it is too hot over a long period of time, wildfires can occur, which in turn can cause so-called fire clouds.
  • Satellite images show how a cloud of fire formed over the town of Lyote in Canada after temperatures reached 50 degrees Celsius there and wildfires have already erupted.
  • Fire clouds are very destructive because instead of rain they usually cause storms or lightning, which further fuels fires.

It’s a vicious cycle: if it’s too hot in an area for a while, wildfires can occur, which in turn leads to so-called fire clouds (PyrocumulonimbusDriving ability. This is a type of cloud that occurs as a result of firestorms and is accompanied by severe storms, thunderstorms, and, in rare cases, tornadoes.

This is what happened in the Canadian town of Lyot, south of Vancouver. Record 50-degree temperatures have prevailed there for the past few days. On Wednesday, the Forest Fire Service reported two fires in the county. Then another devastating bushfire broke out on Thursday – during which it destroyed 90 percent of the village. A satellite image posted by meteorologist Dakota Smith, an employee of the Collaborative Institute for Atmospheric Research in Colorado, shows exactly how fire clouds formed over Lyut Wednesday evening before the Great Forest Fire.

When you see clouds above bushfire smoke, you usually think of thunderclouds. Rather, it is Pyrocumulonimbus. By the way, another name for fire pull is “Cumulus Flammagenitus‘, which means something like ‘originated from a flame’.

This is how clouds of fire appear تظهر

Thunderstorms usually form when a lot of warm, moist air rises from the ground into the sky. If this enters the lowest part of the atmosphere, the air cools and returns to Earth. There it heats up again and then rises again. Experts call this cycle convection – it leads to the formation of a thundercloud.

However, if warm air does not rise from the ground, but from a smoky fire, then instead of thunderstorms, the fire clouds described above arise. They appear as an anvil and can generate rain, like other clouds. Often, however, they do not produce the much-needed droplets, but rather powerful explosions of air, which are known as “avalanche explosions”.

These push dry air back into the ground, which means that the embers and smoke of the fire travel over long distances. The flames that ignited the storm in the first place also caught fire. Pyrocumulonimbus storms can also generate powerful lightning strikes that start new fires. The largest cloud of its kind was seen over California in September 2020 – an area three times the size of Seattle.

Picture of a pyrocumulonimbus cloud over California wildfires in 2020.

Picture of a pyrocumulonimbus cloud over California wildfires in 2020.

Talia Dockery

In the worst case, the convective air in the pyrocumulonimbus cloud bank forms a circular plume and the storm turns into a “fire cyclone”. It happened near Canberra, Australia in 2003 after a forest fire raged around the city for two weeks.

It can also happen that not only one firestorm is formed, but several at the same time. In the spring of 2009, for example, massive wildfires blazed in southeastern Australia over an area of ​​about 4,500 square kilometres. Three separate pyrocumulonimbus storms occurred – some reaching altitudes of nearly 14,500 metres.

Sometimes even storms invade the stratosphere

With warmer temperatures and drier air, wildfires are becoming more common. Because this increase in frequency and intensity, there are also more firestorms. While a total of 17 such storms formed in Canada, the United States, and Mexico in 2002, two decades later there were 25 in western North America alone, according to a Yale360 environmental magazine report.

These storms can rise so high that they penetrate the stratosphere and smoke from the ground flows there. It can be stored there for months or even years. A 2018 study showed that a large pyrocolonimbus cloud could send as many smoke particles into the stratosphere as a medium-sized volcanic eruption.

This text has been translated from English. You can find the original Here.

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