All weather systems
“Storm formation flight - squadron of thunderstorms marching in military precision”
Formation
Cold front or convergence line triggers line of thunderstorms
Impact
Produces most damaging straight-line winds
Technical specs
Wind60-100+ mph gusts
RegionsGreat Plains, southeastern US, other continental areas
rare
Famous encounter
The 2012 North American Derech - A massive squall line event
Etymology
Nautical term 'squall' meaning a sudden violent gust of wind