The ice moves inexorably ashore, crackling as it goes like thousands of windows breaking. In minutes, it's moved from the shoreline of a Minnesota lake to the walls of homes along the lake.
"It was just pushing and breaking and pushing and breaking," Darla Johnson, who made a video of Saturday's "ice tsunami" on Mille Lacs Lake, told CNN affiliate WCCO-TV in Minneapolis. Johnson's video had more than 275,000 views on YouTube by Monday morning.
And once you watch it, you can't stop. It's like a sci-fi movie, and there's certainly science involved. On the Minnesota lake, about 80 miles north of Minneapolis, northerly winds of 30 mph to 40 mph picked up melting ice off the lake and pushed it onshore, CNN meteorologists said.
"It basically has the same mechanism of an iceberg," said CNN's Todd Boreck. "Winds, but more so ocean currents, allow icebergs to drift. Same premise: A chunk of ice (relatively shallow) was pushed by a strong, sustained wind. The momentum of the ice sheet overcame the friction of the land."
The same phenomenon was seen Friday on Dauphin Lake in Alberta, about 75 miles northwest of Winnipeg, where a wall of ice up to 30 feet high destroyed six homes and damaged 14 others, according to a report from the Canadian Broadcasting Corp.
"This is worse than a flood, because with a flood, the water just goes through and it's finished. With this, there's still so much ice out on the lake that if the wind picks up again, it could start all over," homeowner Elaine Davis told the CBC.
"You know you've got cement, concrete blocks and steel, and the ice goes through it like it's just a toothpick," Dennis Stykalo, who also lost a home to the ice, told the CBC. "It just shows the power. There is nothing you can do; you just get out of the way and just watch."