There are few things more picturesque than an array of autumn leaves reflecting on the smooth surface of a lake, seen from a canoe quietly traversing the waters.

But even with a warmer-than-normal fall, cool evenings and freezing temperatures across most of the state mean water temperatures in Minnesota’s lakes and rivers are steadily dropping.

While safety is always a priority when venturing out on the water, no matter how warm it is, the Minnesota Department of Natural Resources urges extreme caution for those venturing out hunting, fishing or paddling before freezing.

Even for good swimmers and in good physical shape, a fall into cold water can shock the body, and with fewer people on the water at this time of year, the chances of finding help nearby if a the boat capsizes. The rapid cooling of the arms and legs while submerged in cold water makes swimming more difficult. The drowning of a ranger in Voyageurs National Park last month underscores the danger.

The DNR’s advice is simple: Wear a personal flotation device.

“This time of year, the water is especially unforgiving,” Capt. Adam Block, DNR’s water law administrator, said in a statement released by the agency. “Unfortunately, over the last few weeks we have seen a number of people on the water either not wearing life jackets or not even wearing them. If there’s one thing you can do to make sure you get home safely at the end of your journey, it’s to wear a life jacket.”

DNR figures show more accidents are reported during the busy summer months, when it seems every Minnesotan finds a way to enjoy the water. However, more fatal accidents occur in the fall and spring in colder water.

In addition to life jackets, the DNR strongly encourages boaters to evenly distribute weight in the boat; pay attention to a boat’s posted weight limits; watch for bad weather (especially strong winds); always carry a mobile phone; and let a friend know where you’re going and when you’ll be back.

The Minnesota DNR offers tips on how to survive a fall into cold waters at mndnr.gov/safety/boatwater/cold-water.html. It includes a step-by-step guide on what to do in the first minute, first 10 minutes and first hour after an accident.