Ice is never completely safe. That said, many people successfully venture out on frozen lakes, streams and rivers each winter without breaking through the ice. While ice should never be considered completely safe, there are ‘acceptable’ thickness when the risk is lower.
There are steps you can take to gauge the the potential ice safety like observing the ice color, measuring its thickness and being aware of external factors such as temperature, local conditions and local knowledge of the frozen waterways in the area.
As you can imagine, the thicker the ice the more weight it will support, however the ‘quality’ of ice is also a big part of the equation. New ice that is clear or transparent is the quality ice we are looking for but there are weaker types of ice that should be avoided.
- Clear ice tends to be newer and the strongest.
- White to opaque ice will have air pockets in it and is weaker than clear ice.
- Ice that is colored light gray to dark black is unsafe and you should avoid this type of ice as it may not hold a load.
- Mottled and slushy or what some people refer to as “rotten” ice – because of its texture. This ice is thawing and slushy and may look good at the top but is compromised through the ice layer. This type of ice will likely give way when a load is introduced.
“Thick and blue, tried and true; Thin and crispy, way too risky.”
After observing the ice to appear safe the next step is to test the thickness of the ice. Let people know where you will be and that you may venture out on the ice before you head out. Use the buddy system and bring ropes for the operation. A floatation device is always a good idea especially when first testing the thickness of ice covered water.
An ice auger is a great tool for drilling through the ice but axes can also work in many cases. With a hole drilled through the ice get an accurate measurement of its thickness and remember different parts of the lake may have different thicknesses of ice.
Ice is not considered safe to walk on until it is at least 4 inches thick.
At 4” the ice is suitable for ice fishing, cross-country skiing and walking and can support about 200 pounds.
At 5 inches of new clear ice should be enough to hold a single snowmobile or ATV or about 800 pounds.
At 8-12 inches the ice should be suitable for a small car or a larger group of people.
Light pickup trucks or SUV’s should be ok on new clear ice 12-15” thick.
The more you can determine about the strength of the ice you plan to venture out on the better. Make sure you are prepared for possible emergencies and create an emergency safety plan before you head out on the ice. If there are any doubts about the strength of the ice find an alternative and don’t risk venturing out.
Meteorologist Mike Morrison