The Canadian and United States Coast Guards have issued a joint safety warning as hundreds are expected to take part in Sunday's Port Huron Float Down.
The unsanctioned event typically sees people float on rafts, kayaks and inflatables 12 kilometres down the St. Clair River, mostly on the U.S. side, from Port Huron to Marysville Beach.
Canadian Coast Guard Incident Commander Kathleen Getty said people are urged not to take part in what could be a dangerous event.
"It's cold water, and you're in the water for a long period of time," said Getty. "If you're mixing alcohol with the event, it can be very dangerous. I just think that people don't recognize the stress that they may be putting their bodies in, especially if they have underlying health issues."
Getty said weather also plays a factor noting that strong winds can push floaters across the river, often without proper documentation.
She said if you do choose to participate, wear a life jacket, stay hydrated, keep personal items in waterproof bags, dress appropriately, use a buddy system, and stay close to the shore.
"Ensure that you leave a message with friends and family on shore so that they are not worried or concerned, and they can report it if you don't return to shore when they expect you to. We're encouraging people to ensure that you put your name and phone number on your floatie. As responders, if we find a floatie without a person with it, we need to follow up and assume it's an emergency situation. That can utilize a lot of resources unnecessarily. If we can track down that the owner of the floatie is safe, then that saves a great deal of time and stress and resources to be expended."
The water is very cold, around 19 C, and being in water below 21 C can lead to hypothermia that impairs physical performance and reduces a person’s ability to swim.
Getty said past float downs have resulted in tragedy. In 2014, a 19-year-old experienced swimmer drowned during the event. The U.S. Coast Guard and local, state and federal partners including the Canadian Coast Guard mounted a significant search and rescue effort that was eventually suspended after 21 searches lasting more than 36 hours.
In 2016, high winds and a heavy downpour led to approximately 1,500 participants requiring assistance when they landed on the Canadian shoreline at Sarnia and Corunna, leaving them stranded. Some had injuries and were suffering from hypothermia.
Other agencies helping in the effort include The Royal Canadian Mounted Police (RCMP), Canada Border Services Agency (CBSA), Ontario Provincial Police, Sarnia Police, and Sarnia Fire and Rescue.
Commercial and motor vessel traffic on the river will be restricted between 12 p.m. and 8 p.m. to ensure participant safety.