Storm chasers group, Basehunters, captured this beautiful shot of a massive supercell cloud near Clareton, Wyoming on May 18, 2014. The picture features a massive rotating updraft of a supercell thunderstorm. Supercells are the largest, strongest and longest-lasting thunderstorms and usually feature a rotating updraft as seen in the picture above.
Supercells often form when cold fronts, massive columns of colder air, move into the area. As the cold front approaches, warm, moist air is forced to rise which creates an updraft. The air moving upwards begins to rotate or spin creating a mesocyclone. As the water vapor rises, it condenses creating the massive swirling clouds inside the supercell thunderstorm.
Despite their scary appearance, supercell thunderstorms typically do not produce tornadoes. They do however, produce huge amounts of rain, hail, and strong winds. They can occur anywhere in the world but are fairly common in the Great Plains of the central United States. They typically remain isolated from other thunderstorms and can last for several hours.
Below is another picture of a supercell thunderstorm.