For many outdoors enthusiasts, a frozen pond or lake is an invitation to fun. A sheet of ice brings out ice skaters, hockey players, snowmobilers, and ice fishers, to name just a few. However, a sheet of ice also can bring danger to those on it. Learn how to judge safe ice thickness before you set out for a day of winter adventuring.
General Ice Safety Rules
One of the most important things to remember is that ice is never 100% safe. Bodies of water do not freeze uniformly. Ice can be 2 feet thick in one place and just a few inches thick a few yards away. In addition, snow cover, currents, and other factors can affect the thickness and the stability of ice. Take it from the land of 10,000 lakes, as the Minnesota Department of Natural Resources offers these important ice safety tips and guidelines:
- Check the thermometer, not the calendar. Meteorologist John Davitt notes that it takes at least four days of below-freezing temperatures to form ice that’s safe to walk on — and that only applies to ponds or lakes with no currents. An AcuRite personal weather station is one way to track the temperature history in your area.
- Check with local experts and sources to get current ice reports and warnings about hazardous areas to avoid.
- Always let someone know where you are going and when you expect to return.
- Keep your cell phone with you so you can call for help if needed.
- Monitor weather conditions while you’re out by carrying a portable weather device.
- Check ice thickness every 150 feet.
- Be especially careful on snow-covered ice. Snow has an insulating effect that can slow down freezing. In addition, the weight of the snow reduces the amount of weight the ice can safely support. Finally, snow obscures the ice, making it harder to see visual cues to the strength and safety of the ice.
Guide to Safe Ice Thickness
So, how thick does ice need to be to walk on it safely? This general gauge gives safe ice thicknesses to support different types of activities:
- Less than 4 inches: Stay off the ice.
- 4 inches: Walking, ice fishing, ice skating, or other activities on foot are permitted.
- 5 to 7 inches: Snowmobiling or riding ATVs are safe.
- 8 to 12 inches: Driving a car or small pickup is allowed.
- 12 to 15 inches: Driving a medium-sized truck is safe.
Visual Cues for Ice Safety
While the thickness of the ice can give you a general guideline, you can’t rely on the thickness alone since many other factors also have an effect on ice strength. These visual cues should also factor into your judgment:
- Clear ice or new ice is the strongest type of ice. If the ice is white, cloudy, or milky, double the safety measurements.
- Ice with slush on top is not safe. It may mean that the ice is not freezing from the bottom.
- Avoid areas of ice with logs or other protruding debris.
- Even just a few days of warmer temperatures can cause cracks to form, weakening the ice around them.
More Winter Fun
Looking for more winter outdoor fun? Check out our other blog posts for more safety tips and ways to get the most out of the great outdoors in winter.
Finally, you don’t have to brave the dangers of a frozen lake to enjoy ice skating outdoors — you can do it in your own backyard. Check out this blog post from one of our AcuRite community members who built a backyard ice rink for himself and his family.
What outdoor winter activities do you enjoy? Let us know in the comments!