Participants in the annual Port Huron Float Down

Canadian authorities in Sarnia, Ontario had some unexpected guests on Sunday, August 21, after approximately 1,500 US residents accidentally floated to Canada during the Port Huron Float Down, an annual event on the St.Clair river that divides the US state of Michigan from Ontario. The trespassing flotilla of dinghies, inner tubes and rafts was no match for strong winds that whipped up throughout the afternoon.

Most of the unintentional border crossers arrived without passports, documentation, phones or arrangements to get back home, creating a major problem for law enforcement and emergency responders on both sides of the river.

"They [the boaters] were pushed over pretty quickly, and because they had no control over these dinghies and the wind was basically directing them and the current, they ended up over here," said Sarnia Police Constable, John Sottosanti. "Others tied numerous dinghies together to try and keep together and hopefully move as one, but they were not successful at all."

Police, border security and coast guard agencies from both sides of the border helped round up the wayward Americans and return them to Port Huron, Michigan. Emergency response crews from several Sarnia chemical plants also helped with the situation, as a number of boaters landed near their facilities. Individuals who had no means of returning to the US were placed on 20 buses provided by the city of Sarnia. There is not expected to be any further repercussions for these individuals who entered Canada accidentally, albeit legally.

Participants in the Port Huron Float Down meet every year at Lighthouse Park, Mich., where Lake Huron feeds the St. Clair River. They then launch themselves from the bank early in the day and ride the current south approximately 14 kilometres, to land at Chrysler Beach, Marysville, Mich.

All 1,500 or so US residents who accidentally strayed into Canada eventually made it home after a tiring day.

A similar incident — though one far smaller scale — took place last month in the other direction, when two Canadian teenagers were apprehended illegally crossing the border into the United States while playing Pokémon Go, the augmented-reality mobile-based video game.

The map below shows the location of Sarnia, Ontario, at the southern end of Lake Huron on the St.Clair River.