Winter is a wonderful time. Yet, with all the natural beauty the season offers, winter also comes with its fair share of possible dangers. Take ice, for instance. Do you know when winter ice is safe?
According to Minnesota’s Department of Natural Resources (MN DNR), there’s no sure answer, and there’s no such thing as 100-percent-safe ice. No one can accurately judge the strength of ice since strength is based on so many different factors. These factors include: appearance, age, thickness, temperature, depth of water under ice, size of body of water, water chemistry and currents, distribution of the load on ice, and local climate conditions.
Some “cold, hard facts” about ice, courtesy MN DNR:
New ice is usually stronger than old ice. Four inches of clear, newly‑formed ice may support one person on foot, while a foot or more of old, partially‑thawed ice may not.
Ice seldom freezes uniformly. It may be a foot thick in one location and only an inch or two just a few feet away.
Ice formed over flowing water and currents is often dangerous. This is especially true near streams, bridges and culverts. Also, the ice on outside river bends is usually weaker due to the undermining effects of the faster current.
The insulating effect of snow slows down the freezing process. The extra weight also reduces how much weight the ice sheet can support. Also, ice near shore can be weaker than ice that is farther out.
Booming and cracking ice isn’t necessarily dangerous. It only means that the ice is expanding and contracting as the temperature changes.
Schools of fish or flocks of waterfowl can also adversely affect the relative safety of ice. The movement of fish can bring warm water up from the bottom of the lake. In the past, this has opened holes in the ice causing snowmobiles and cars to break through.
For additional in-depth information on ice and ice safety, visit the MN DNR web site.