The following info is from the Minn. DNR. I understand they know a little about ice there.
General ice thickness guidelines
ice thickness guidelines
For new, clear ice only
UNDER 4" - STAY OFF
4" - Ice fishing or other activities on foot
5" - 7" - Snowmobile or ATV
8" - 12" - Car or small pickup
12" - 15" - Medium truck
Many factors other than thickness can cause ice to be unsafe.
White ice or āsnow iceā is only about half as strong as new clear ice. Double the above thickness guidelines when traveling on white ice.
The following site contains a video that shows just what to do if you end up in the water. Please watch it, it may save your life. I know Iām going to be a lot more prepared this year and as cautious as ever, but you never know.
You didnāt mention Minnesota DNR says that 38 inches of ice is suitable for landing a C-17 at full gross weight. Thatās what some of my friends consider āsafeā ice.
4 to 5 inches of clear new ice is enough for me on foot. 7 to 8 inches is good for an ATV or snowmobile. Keep in mind some waters have warm springs or moving water that can create thin spots. Thus the need for the throw rope previously discussed.[;)]
Your thread about the throw rope inspired me to post this. I hope we all know that numerous factors contribute to ice thickness, quality, and safety. It behooves every one of us to take some time researching about ice safety and rescue. I didnāt want to turn this into a book so I purposely left out a lot of useful information. For example, we donāt have to worry about white ice just now as nearly all the ice we encounter this time of year will be new clear blue ice. I hope that as the season progresses we can all share what we know and give specific warnings such as, āMake sure to go wide around the first spring at Lincoln Beach as the ice can be weak where the warmer water flows in.ā Etc.
Thanks for posting that reminder. I see from the MN recommendations that they have changed their recommendations slightly. Just a couple years ago they posted that 3" was safe ice for single individuals and 4" was recommended for a group of individuals moving in single file. From the Farmers Almanac you can still see the older recommendations - Safe Ice Chart
And since most folks go as a group, the 4" is probably a better lower limit. Iām good also with 5" for my snowmobile as the weight is spread out over a larger area. For a quad, Iād go with 6" or better because of the weight concentration at just the wheels contacting the ice surface.
But like Mike, I know folks that think anything under a foot thick is completely unsafe. [;)]
Speaking of warm springs, a good example is this place, the Big Hole area south of Strawberry Marina. Two vehicles in the last three years have gone in at that spot while the surrounding ice was 18-24 inches thick.
Hey just a little south of your yellow area at that island is where a snowmobile went through last yearā¦ Itās weird down around that island, donāt trust itā¦ Later J
Iām not very smart as to why ice freezes different from year to year, but the ice on Tony this year seems to be frozen in vertical crystals and is a little crumbly even as fresh frozen blue iceā¦ Iām not sure why, but itās breaking different than other years and doesnāt seem as strong as I usually think new black ice isā¦ Got the spud bar this year and I really like that as a tool to test as you goā¦ hope it doesnāt lead me astrayā¦ Later J
