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Thought this (old)article was interesting. Not that many are out driving now but is useful info non the less.

Alaska Science Forum

May 16, 1980

Ice Travelers, Beware!

Article #398

by T. Neil Davis

This column is provided as a public service by the Geophysical Institute, University of Alaska Fairbanks, in cooperation with the UAF research community. T. Neil Davis is a seismologist at the institute.

One of Nature's nasty tricks for the unwary traveler is the little known fact that there is a particularly dangerous speed for crossing lake or ocean ice. Moving either more slowly or more rapidly than this dangerous critical speed makes for a safer crossing.

It is not immediately obvious why there is a critical speed at which a moving object--a truck, a snow machine, an ice skater or a taxing aircraft-- is most likely to break through the ice. The reason is that the object moving across the ice at other than very slow speed creates a wave in the ice, i.e., a moving deflection of the ice. Just as a sound wave moves at fixed speed through air, the wave in the ice moves at fixed speed. The speed of the wave in the ice increases with the ice thickness and the depth of the water beneath the ice. A typical speed for the wave in foot-thick (30 cm) sea ice over water 20 feet deep (7 meters) is 20 mph (32 kph).

Now if the object creating the wave moves at the same speed as the wave, the object stays with the wave, just as a successful surfer stays with a water wave riding into the beach. Staying with the wave is great fun for the surfer, but it is disaster in the making for the object riding with the ice wave. The trouble is that the effective weight of the object on the ice builds up and becomes many times the static weight.

Engineers have known about this dangerous phenomenon for many years, but only this year a new method of calculating the stresses on the ice has made it possible to learn how much the effective weight increases when an object moves at the critical speed across the ice. Devised by Professors Howard Bates and Lewis Shapiro of the Geophysical Institute, the new method shows that a 10-ton truck moving at critical speed across ice can create the same breaking stress as a slowly-moving truck weighing 100 to 150 tons. Moral: drive slowly on ice to avoid hitting the critical speed.

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I would like to add driving slow speeds for the safety of the people sitting in their fish houses as well. I have feared for my life a time or 2 with the way some people drive around fish houses.

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Great safety post Barsky. Some people thik the lake is a race track and come to shore way to fast,great way to get a blow-out at the landing.

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I was on a lake last year just sitting out in the open on a bucket enjoying a very nice day on the ice. Along came these, what looked like high school kids, having fun zipping along in their little truck. It was unbelievealbe what happened.

They were going fast and went into a spin right by a bunch of shacks. It was slippery ice and they kept spinning for a long time. They went right through all the shacks and never hit one. I couldn't believe they could be spinning out of control like that and be lucky enough not to hit anything. Somebody was watching down on them and the folks in the shacks that day.

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I saw something similar to this last year out on Lake Francis, only they hit one of the houses. Didn't damage it badly, I think they just glanced off of it, but still did some damage. I was too far away to see a plate number else I would have called it in.

It always makes me nervous when the ice is as thin as it has been this year when someone drives too close. 2 weeks ago out on Horseshoe the old man and I were out and a car was coming off the lake, he was 20 feet away (too close for me). Now I've only felt the ice drop and shift like that a few times in my 12 years of ice fishing and it scares the living daylights out of me every time it happens. When you can actually feel the ice fall from under you, I think that is one of the worst feelings in the world.

This is a very good thread. I had read something on this, but couldn't remember what it had said. I'm glad you posted this info, it is very good information. Going too fast can and a lot of times will cause a break through, I just hope I don't see or experience it. EVER!

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Just a question along the lines of safety while driving on the ice. When I drive on the ice, I roll my window down and crack my door open, trying to give myself the quickest opportunity to bail out in case something does ever happen. Is this the right thing to do or am I doing it all wrong?

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That is actually the best way to do it. If you go to the DNR Website they have 2 ice fishing seminar type things that you can download and listen to in Windows Media Player. They are about 30 min apiece and they talk about the "safest" way to drive on the ice. In there they talk about driving w/o your seat belt on, windows down and/or door open. They also recomment leaving windows open while it is parked, though I don't remember why. If you like you can go get them and if you can't find them, let me know, I have them on my computer at work and can post them on my webserver for ya to download.

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I know this, I always travel on the ice, unbuckled, with my door open...which makes for a funny sight driving 3 miles out up on lake vermilion...

I ain't no captain, I don't plan on going down with my ship

grin.gif

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That's good to know. Always wondered if I was driving on ice the way a person is suppose to. I wonder though about driving on ice without a seatbelt. I know a couple of guys that have gotten busted for drinking and driving out on the ice by cops on Mille Lacs. Apparently driving on the ice is no different than on a road...same laws apply. Could somebody get busted for driving on the ice without a seatbelt then??? confused.gif

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this thing i listen to on the dnr site has a dnr officer and another guy, not sure what he was but the dnr officer said on there that it is the ONLY time it is allowed to not wear your belt. I think that is what he said but you'd have to listen for yourself to make sure.

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  • Your Responses - Share & Have Fun :)

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