Record heat and increasing wildfires are creating firestorms which can produce their own lightning above British Columbia, Canada.Pyrocumulonimbus clouds are formed when smoke and heat from large fires rises high into the sky. These thunderheads can produce their own weather, sometimes including tornadoes, which can then ignite new fires. It is a vicious circle.Lytton, located 153km (95 miles) south Vancouver, reached 121.2 degrees Fahrenheit (49.5 Celsius) Tuesday, setting a new national record. The heat wave came before a wildfire, prompting the mayor of Lytton to issue an evacuation order for all 250 inhabitants. According to City News, 90 percent of Lytton had been burned by the blaze covering 20,000 acres as of Thursday morning.Pyrocumulonimbus cloud at 9,144 m, eastern Washington, August 2019. (NASA Earth Observatory).On Wednesday, the British Columbia wildfire department reported two additional fires.Dakota Smith, a meteorologist at Colorado's Cooperative Institute for Research in the Atmosphere reported that she saw "incredible and massive storm-producing Pyrocumulonimbus Plumes" from satellite images over Lytton on Wednesday.This one was so beautiful that I thought it looked a lot like the #CreekFire. However, these wildfire plumes from pyrocumulonimbus are at a totally different level via @weatherdak https://t.co/L4st9zia24 Rob Mayeda(@RobMayeda), July 1, 2021"Fire-breathing dragon in the clouds"If you see thick, dark clouds of thunderstorms above wildfire smoke it is almost always pyrocumulonimbus. NASA also calls these "fire clouds" cumulonimbus, which is Latin for "created out of flame".Thunderstorms are formed when a lot of warm and moist air rises from the ground into the sky. It cools as it reaches the lowest point of the atmosphere. Then it sinks closer to Earth, where it heats up again and rises. This cycle of rising/falling air is called convection and it gives rise to cumulonimbus or thunder clouds.However, convection can create pyrocumulonimbus clouds when the heat and moisture rises from a smoky fire rather than the ground.(Bureau of Meteorology Australia)These anvil-shaped clouds can produce rain just like other thunderstorms. They can also unleash powerful blasts of air, known as "downbursts", which are more like water droplets than they are. These downbursts, which push dry air down towards the ground, can spread a fire's embers across great distances. This fuels the original storm.NASA refers to pyrocumulonimbus thunderstorms as the "fire breathing dragon of clouds". They can also produce hundreds of lightning strikes, which can in turn spark more fires.The Creek Fire, a California fire, created one of the most massive types of these clouds in September 2020. It covered 175,893 acres or 275 miles. This is more than three times as large as Seattle.Pyrocumulonimbus cloud above the Creek Fire, California, 2020 (Thalia Dockery/Business Insider).Sometimes, the storm can transform into a "fire tornado", a twister-of-fire, when the convecting air from a pyrocumulonimbus clouds bank forms a swirling circular column.After a bushfire had raged for two weeks, this happened in Canberra, Australia, 2003.Multiple firestorms can be generated by a single fire. In February and March 2009 huge bushfires erupted over 4,400 km (1,700 miles) in southeastern Australia. They also generated three distinct pyrocumulonimbus thunderstorms, some reaching heights of 14km (8.6 miles) above Victoria.Australian bushfires created the Pyrocumulonimbus cloud, 1 February 2020. (Brook Mitchell/Getty).Climate change could play an important roleHigher temperatures and dryer air are linked to more frequent and intense wildfires. Wildfire-generated storms are also becoming more common as wildfires grow in size and intensity.Canada, the US and Mexico experienced 17 of these storms between 2002 and 2003. Yale360 reported that two decades later the average number of pyrocumulonimbus storms per year had increased to 25, in Western North America.These storms can reach so high that they penetrate to the stratosphere, a layer of atmosphere that begins at 50 km (30 mi) up. They funnel smoke from below into the sky. It can remain up there for many months, or even years.A 2018 study showed that large pyrocumulonimbus clouds can send so many smoke particles into space that they are comparable to a small volcanic eruption.Business Insider originally published this article.Business Insider has more:
