What the Heck is Going On With This Ice?

Fellow Flosser Adrienne emailed to ask, “Um, can you explain this for me like I'm five?”

Attached was a video—shot by Nadalie Thomas at Medicine Lake in Plymouth, Minnesota—that’s been making the rounds on the Web the last few days, showing a bizarre mound of ice shards piling up on the shore of a lake. Nature, you crazy.

What’s happening, meteorologist Jerrid Sebesta says, is that warm temperatures and wind come together to weaken the ice on Minnesota’s many lakes and then push it against the shore, where it shatters into tiny shards and piles up on the beach.

These little ice hills look cool as they form, but the phenomenon can also be dangerous. With enough ice and enough wind, these pile-ups can be driven deep on to shore, where they destroy buildings—and can hurt and kill people.