Wow. This here is what you would call a gigantic rotating supercell!
by David Ng
A supercell is a thunderstorm that is characterized by the presence of a mesocyclone: a deep, persistently rotating updraft. For this reason, these storms are sometimes referred to asrotating thunderstorms. Of the four classifications of thunderstorms (supercell, squall line,multi-cell, and single-cell), supercells are the overall least common and have the potential to be the most severe. Supercells are often isolated from other thunderstorms, and can dominate the local climate up to 32 kilometres (20 mi) away. (From Wikipedia)