How is a gas able to fill a container of any size or shape

The constant motion of particles in a gas allows a gas to fill a container of any shape or size. Particles in a gas are in constant, random motion. The motion of one particle is unaffected by the motion of other particles unless the particles collide.

supercell thunderstorms are perhaps the most violent of all thunderstorm types, and are capable of producing damaging winds, large hail, and weak-to-violent tornadoes