Ice strength dependent on several factors
Nicole Tavenner
Ice is beautiful, but can also present a safety hazard.
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News from the Confederated Salish and Kootenai Tribes, Natural Resources Department
FLATHEAD INDIAN RESERVATION — According to Cindy Benson at the Tribal Fisheries Program, “The only safe ice is at an ice skating rink.” So if you plan to ice fish, the basic question is always the same: Is the ice safe now?
As ice starts to form over lakes and reservoirs, the Division of Fish, Wildlife, Conservation and Conservation gets lots of calls from outdoor enthusiasts who want to know about ice conditions.
Here are a few general guidelines for use by winter recreationists to help judge ice safety:
• Ice may not be the same thickness all over.
• Stay away from “stickups” like brush, logs, plants or docks.
• Stay away from multiple pressure cracks.
• Spread out because crowds can add too much weight in the same area.
• Be extra careful on rivers and streams. The ice may look thicker than it really is, because moving water wears ice from underneath.
It’s important to also study and know which ice is the strongest.
• Clear blue ice is the strongest, and it still takes four inches to safely hold a single person.
• Milky, honeycombed ice that has air bubbles or snow crystals trapped in it can be much weaker that clear blue ice.
• Water currents under the ice or springs can create weak spots.
• Never trust the ice on a river or stream; it can be several feet thick in one place, and unsafe in others.
• Heavy snow cover insulates ice and prevents it from freezing as evenly or as quickly as it would if the snow were not there.
It’s impossible to judge strength of ice by its appearance, thickness, daily temperature, or snow cover alone. Ice strength is actually dependent on all four factors, plus water depth under the ice, the size of the water, water chemistry, currents, and distribution of the load of the ice.
Before you go out on the ice, test it’s strength and be prepared. For more information on ice safety call Cindy Benson or Germaine White at (406) 883-2888.
