10 Jun 2014

Supercell thunderstorm hits Germany with over 100,000 lightning strikes

A violent supercell thunderstorm formed over western Germany on Monday evening, leading to the deaths of six people and causing significant transport disruption.

As the storm swept eastwards, it battered the North Rhine-Westphalia state with torrential rain, hail, frequent lightning and damaging gusts of wind.

Trees and power lines were blown down, blocking roads, cutting power supplies and leaving debris strewn across streets. 

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The severe weather followed a summer heatwave which has seen temperatures across Germany soar above 30C through the weekend, with some places in the south of the country reaching 36C.

What is a supercell?

A supercell is a particularly large and violent thunderstorm that is driven by a rotating updraught of air that sends huge amounts of heat and moisture high up into the atmosphere.

They often occur following a heatwave, when a large amount of heat builds up at the surface, trapped by an inversion, which stops the air from rising.

An inversion is effectively like putting a lid on a saucepan of boiling water, keeping it contained and stopping it from boiling over.

However, as soon as this inversion is eroded, the air rises explosively upwards. When this happens, all of the heat energy from the surface is converted into driving a vicious thunderstorm, causing severe weather.

Due to the huge amounts of energy involved, supercells effectively become small weather systems in their own right and generally occur in isolation from other smaller thunderstorms.

Over 100,000 lightning strikes

Last night’s supercell thunderstorm produced an estimated 113,708 lightning strikes (see map below) across Germany between 2pm Monday and 8am Tuesday, as it spread north eastwards across the country.

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Not only was there frequent lightning, but also torrential rain and very strong, gusty winds. The video below, posted on Instagram yesterday evening, shows the impact of the storm on Essen.

//instagram.com/p/pCRmZ_n0Wc/embed/

While this particular storm doesn’t seem to have produced a tornado, such storms that form in the US are renowned for doing so.

Further thunderstorms are expected in Germany in the next 24 hours, before high pressure builds later in the week, settling the weather down.

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