If you see something like this coming your way when you’re out on the water this weekend, head back to shore.
Andrew Ballard and his father were enjoying a sunny afternoon of fishing on Lake Michigan last week when they saw an enormous wall of fog moving towards them. As the fog approached, it swallowed up the lake and all the blue sky above it.
Ballard, 24, filmed the ominous clouds as it rolled in towards their fishing boat.
This strange weather pattern is known as an advection fog, in which warm air moves over cold water, according to meteorologist Deb Elliot.
“Fog develops as the air is cooled and is then moved along by wind. It can very thick and extensive; if they were swallowed up in it, their visibility could drop to almost zero.” Elliot told The Detroit News.
While it appears to be calm on the outside, the inside of advection fog has strong winds, cold temperatures and almost zero visibility.
Ballard and his father got lost in the fog, but were able to navigate back to the shore using their GPS system.
So, if you see an ominous fog rolling your way, it’s best to hightail it back to shore.