Canadian authorities stopped an invasion: 1,500 people on inflatable rafts and boats that drifted across the border from Michigan during high winds on the St. Clair River.
The 12km Port Huron Float Down is an annual event on the river that divides Michigan from Ontario, Canada. But the winds turned it into an international incident Sunday.
"The event has no official organiser and poses significant and unusual hazards given the fast-moving current, large number of participants, lack of life jackets, and as was the case this year, challenging weather conditions," the Sarnia, Ontario, Police Service said on its website.
Police said it took hours for a bus service, Sarnia Transit, to transport approximately 1500 US citizens back to Michigan.
"They were unprepared to be stranded anywhere," Staff Sgt. Scott Clarke told the Times Herald.
"It was a bit of a nightmare, but we got through it," he said. "There were long waits and long lines. They were cold and wet, but they all made it home."
The event started at Port Huron's Lighthouse Beach and was supposed to end at Chrysler Beach in Marysville.
Sarnia city workers spent several hours Monday picking up beer cans, coolers, rafts - even picnic tables - that washed up on the Canadian shore, said spokeswoman Katarina Ovens.
"I guess they were on the rafts," she said of the picnic tables.