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noun [countable]

an extremely severe thunderstorm characterized by a very strong rotating wind which blows upwards and lasts for a long time



'Incredible Wyoming supercell caught on video … It almost doesn't look real. The group Basehunters Chasing tweeted out photos and a link to a time-lapse video of a supercell over Clareton, Wyo., that pummelled the area with rain and hail.'

Toronto Sun 20th May 2014

'Expect some storms to become supercellular – with attendant risk for hail/damaging winds along with a few tornadoes – with the risk peaking from late afternoon through mid evening.'

Newsroom America (news feed) 29th April 2014

To the uninitiated, the word supercell might suggest a brand of particularly powerful battery. However if you're a geography enthusiast, or live in a part of the world especially prone to extreme weather systems, then you'd know that it refers to a very severe thunderstorm, potentially one of the most dangerous we can witness.

supercells are the cause of most significant tornadoes in the USA, but can occur anywhere in the world under the right conditions

The word supercell was splashed (excuse the pun) across the global headlines in May 2014, when a storm of this category hit the state of Wyoming in North America. The action was caught on video by storm chasers, who repeatedly filmed and then drove away from the spectacular meteorological display. Within 48 hours of being uploaded this amazing time-lapse video had gone viral, bringing a breathtaking freak of nature to the desktops of millions.

So what exactly is a supercell? In very basic terms it's a rotating thunderstorm, characterized by what's technically known as a mesocyclone. This is a very strong, long-lasting, upward current of air which usually rotates in a clockwise direction, whipping up clouds into a thunderous vortex. As supercell storms typically follow a path to the right of the prevailing wind, they are often described as right-movers (left-movers, i.e. following a path to the left, are also possible, though usually less severe and enduring than right-movers). Supercells tower up into the sky, and though extremely dangerous, can look hauntingly beautiful. Some very impressive images can be found here.

As you'd expect, supercells produce some pretty extreme weather conditions. They can generate winds of more than 100 miles per hour, torrential rainfall, flash floods, and hail stones the size of golf balls. Downward currents from these astonishing feats of nature can pose a very serious threat to people, property and wildlife in their path, and the storms may last for several hours until conditions change sufficiently to break them apart.

Supercells are the cause of most significant tornadoes in the USA, but can occur anywhere in the world under the right conditions. They are, however, the most uncommon type of thunderstorm.

Background – supercell

The first ever storm to be identified as a supercell was in fact in the UK, over the town of Wokingham in 1962. British meteorologists Keith Browning and Frank Ludlam were the first to undertake a detailed study of such a storm.

The word supercell most often occurs as a modifier of storm/thunderstorm (i.e. supercell storm), and a counterpart adjective supercellular also exists. Within the terms, the word cell is used in its technical sense relating to an identified spike (sudden increase) in radio energy which develops and gradually subsides. This is combined with super-, a productive prefix which conventionally represents the idea of being large or extreme (compare e.g. superrich, supersize, superinjunction). Super- originates from the same term in Latin meaning 'above, beyond'.

by Kerry Maxwell, author of Brave New Words

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This article was first published on 17th June 2014.

Open Dictionary


a form of location that involves the underwater detonation of a bomb which causes sound waves that are picked up by ships

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