In the united states, winter thunderstorms often occur when cold air aloft moves over the region.

In the united states, winter thunderstorms often occur in winter along the west coast of North America when cold air aloft moves over the region.

Winter thunderstorms are usually common between November and April during winter and spring seasons where warm tropical air flows northward and collides with the cold dry air. This type of situation easily creates winter thunderstorms.

The answer i think is d

Answer volcanic eruptionsseismic waves from earthquakes;