What is a Supercell

Find out how this phenomenally powerful and deadly thunderstorm forms.

In this image we can see the culmination of a highly organised thunderstorm, commonly referred to as a ‘supercell’. Supercells are incredibly rare, with significantly fewer sightings than singlecell or multicell variants, but their unique properties make them incredibly dangerous when they do occur.

A supercell thunderstorm is similar to a singlecell storm and tornado in that it has a single main updraft. However, unlike the latter it is phenomenally strong, reaching estimated speeds of 240-280km/h (150-175mph). It is so strong that it can easily upturn cars, uproot trees and even destroy entire buildings.

The main difference between a supercell storm and other types is the presence of rotational energy. This causes the updraft to rotate (referred to as a ‘mesocyclone’) and helps to generate extreme weather in the supercell’s surrounding vicinity. This can include immense rain showers, massive two-inch-wide hail and violent tornadoes.

Supercells are classified into two types, low-precipitation and high-precipitation. The former supercells tend to formulate in arid climates, such as the high plains of the United States, while the latter are often found in moist climates closer to the Earth’s equator. Regardless of type, supercells form when winds coming in from various differing directions cause a rotational energy to be generated. This helps formulate an updraft and from that, precipitation is produced.

Interestingly, however – and the reason why this image is so amazing – precipitation tends not to fall back down through the supercell’s updraft when generated, instead being carried many miles downwind. Here, though, the supercell is depositing a huge torrent of rainfall directly through the updraft.