SAN FRANCISCO (KRON) — A man on the Northern California coast caught a waterspout on video, and his reaction has sparked tons of laughter on Reddit.

The Pineapple Express has been dumping precipitation on Northern California for two weeks, but it has also brought high winds and waterspouts, otherwise known as tornadoes over water. One Reddit user was enjoying a bit of an afternoon break when he saw a waterspout form over the ocean in front of him.

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Video obtained by KRON4 catches the man’s surprise as he jokingly shouts, “It’s an ocean tornado…sharknado! It’s coming!” The man’s joke refers to a 2013 film called “Sharknado” that shows waterspouts over the ocean lift sharks out of the sea and drop them in Los Angeles.

KRON4 Meteorologist David Spahr broke down how a waterspout forms.

Cold air from the Gulf of Alaska spills over and above us.  With mild air (relatively) at the surface and during these storms particularly, the buoyant mild air rises.  With cold air around it, it condenses out rain, then warms and rises further. The falling rain causes a down draft.

With the ‘warmer air’ (relative to environment) rising up and cold rain falling, this causes a spin which is pulled down to the surface and forms a tornado.

Mabrisa Rodriguez, another meteorologist at KRON4, says that our weather team is tracking the threat of pop-up thunderstorms as the atmospheric river continues to create an unstable atmosphere across the Bay Area. The atmospheric river is expected to continue impacting weather through at least Tuesday of next week. Stick with KRON4 for the latest in weather coverage.