Photo courtesy of the Canadian Coast Guard, via Twitter.

The annual Port Huron Float Down hits the St Clair River this weekend.

Both American and Canadian Coast Guard officials are warning participants to use extreme caution ahead of the unsanctioned event.

“This is an inherently dangerous activity,” a joint statement says. “As first responders, the U.S. Coast Guard and the Canadian Coast Guard recommend that people do not take part in this event.”

Those who choose to take part are strongly encouraged to wear an appropriately sized floatation device, don’t drink alcohol, file a ‘float plan’ with someone on shore who can keep track of you in case you don’t check in on time, and stay near shore and out of the navigation channel.

While many consider it a fun way to spend a summer day, the Float Down has had some serious issues in the past. In 2014 a 19-year-old experienced swimmer drowned during the event. Two years later, high winds and heavy rain stranded roughly 1500 participants on the Canadian side of the border without any ID or means of communication. Some were hurt while others were suffering from hypothermia.

“The U.S. and Canadian coast guards, supported by a large number of federal, state, provincial, and local agencies, are highly trained professionals with limited resources; we embrace that responsibility, but we – as other first responders – cannot be everywhere,” the statement concludes. “We rely on family members and all users of the marine environment to look out for one another, take care of themselves, wear lifejackets, and not drink alcohol while on the water to improve the likelihood that they return home safely.”