BWCA Thin Spots on the Ice Boundary Waters Winter Camping and Activities
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NotLight
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09/04/2015 10:15AM   (Thread Older Than 3 Years)

I'm pretty comfortable skiing on the lake by my house (after christmas), because there's enough snowmobile and car traffic to "test it out for me". But how do you guage where there might be thin ice on a winter BWCA trip. Also, if you have slush, how do you distinguish between that and thin ice?

When I went last year, there was thin ice and open water even in mid-January almost anywhere there was moving water. But couldn't it be anywhere as a result of a spring, or a subtle pinch point on a lake that is really part of a river system? That's what I kind of assume - I could fall through the ice just about anywhere.

 
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OldFingers57
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09/04/2015 11:26AM  
Yes you are correct you can fall thru the ice any place. I have been an Ice Rescue Instructor for 10 yrs now with Dive Rescue International out of Colorado.
Thin ice can be a result of many different things from springs, currents, waterfowl, to obstructions in the water and other bodies of water flowing into a body of water. As for how to know if the ice is strong enough you could "sound" the ice using a large wood dowel/closet rod. Although this can be difficult with snow on the ice. Snow masks the ice and doesn't allow you to see the color of the ice. If there is no snow on the ice you want to look for clear or black ice. Milky ice or ice that is slushy or is kind of honey combed is not strong.
marsonite
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09/11/2015 08:17AM  
quote NotLight: "
I'm pretty comfortable skiing on the lake by my house (after christmas), because there's enough snowmobile and car traffic to "test it out for me". But how do you guage where there might be thin ice on a winter BWCA trip. Also, if you have slush, how do you distinguish between that and thin ice?

When I went last year, there was thin ice and open water even in mid-January almost anywhere there was moving water. But couldn't it be anywhere as a result of a spring, or a subtle pinch point on a lake that is really part of a river system? That's what I kind of assume - I could fall through the ice just about anywhere.

"


An important point to keep in mind is that the water at the bottom of a frozen lake is 39 degrees F. So anything that causes that water to come to the surface will result in thin or even no ice. This could be a shallow pinch point an a lake with a lot of water moving through it or the outlet of the lake. It's the upwelling of this "warm" water that thins the ice, not the movement of the water necessarily.

OldFingers57
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09/11/2015 10:32AM  
Actually current plays a big part in it. That is why river ice is 15% less stronger than lake ice. Also at inlets and outlets the ice is thinner due to currents. Also on rivers straight sections have stronger ice than at curves in the river due to the current.
Wind is another factor in ice formation, if it is windy ice will not form due to the movement of the water. Also waterfowl can keep areas of water open due to there using it. Thus a lake can have a section that is thinner then other sections due to waterfowl keeping it open and the rest of the lake ice is freezing up thicker and then the waterfowl leave the open area and it freezes up but is thinner then the rest of the lake ice.
marsonite
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09/11/2015 03:02PM  
Actually in a lot of spots it's the upwelling of the warmer water from the lake's depth that thins the ice not the current. I used to darkhouse spear pike on Winnie at plughat point, the bay before the outflow of the lake. There was zero detectable current but still the ice in that bay would be 4 or 5 inches thick while the main lake basin was several feet thick.

Obviously moving water doesn't freeze as well, but again, it isn't always just the movement.
OldFingers57
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09/11/2015 03:51PM  
quote marsonite: "Actually in a lot of spots it's the upwelling of the warmer water from the lake's depth that thins the ice not the current. I used to darkhouse spear pike on Winnie at plughat point, the bay before the outflow of the lake. There was zero detectable current but still the ice in that bay would be 4 or 5 inches thick while the main lake basin was several feet thick.


Obviously moving water doesn't freeze as well, but again, it isn't always just the movement. "


So how do you know it was actually the temperature of the water? Or are you deducing that since you saw no current that it has to be the temperature of the water?
marsonite
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09/11/2015 05:10PM  
I guess I assume it, based on other observations too. If you look at the outflow of a lake, sometimes a river will be open for a ways just after it leaves a lake. But if you look a few miles down, it will be frozen. Again, the outflow of a big lake is warm but as it flows in the river it cools off.

Likewise, I grew up near lake Vermilion and quite a few people have broken through the ice in areas that don't even seem to be in narrows but are shallow. Same effect. Slight currents bringing that warm water up.

I guess my point is that you really have to be careful, especially on shield lakes with irregular bottom contours. And don't go anywhere near a major outflow.

Mind you, I agree totally with the general advice you gave. Moving water is bad news.
wingnut
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09/11/2015 07:39PM  
Carry a spud and make it thud. That's the saying for ice fishing and would be a good safe practice for winter trecking on any frozen water as well. If you fish while winter camping you'll get dual use from your spud.
The Arctic Armor ice fishing suit is another great piece of safety gear because if you break through, you float.
2old4U
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09/22/2015 09:42AM  
Also, keep in mind that just because there's snowmobile tracks that doesn't necessarily mean safe ice...they can fly over a thin spot with no problem whereas you moving much slower may drop right through! Best bet go where others have gone on foot or skis, or make a scouting trip with a spud bar to be sure.
09/22/2015 03:08PM  
Ice is never 100% safe. Even when I'm skiing on tracks across a lake I am still careful. You'll know if you hit slush and not thin ice because you won't go through the ice! Your pole will still hit the top layer of ice and ice, depending on the temperature, will form on your skis. I always bring an ice-scraper. I've gone through twice. Once skiing and once walking. Both times I was able to get out without getting wet.
09/23/2015 10:17AM  
The saying that no ice is ever safe it pretty accurate. The only ice that I find to be 100% safe is usually found at the bottom of my glass.

There are so many reasons why thin spots form or why areas never freeze as solid as surrounding areas. Many of them have been covered and both marsonite and OldFingers are correct. Moving water can weaken ice or prevent it from forming and also warm water coming up for the lake bottom can weaken ice (although if warm water is coming up for the bottom that also suggests at least a small amount of moving water for that to happen so both effects are at play there).

If you are unfamiliar with a body of water there are a few things you can do to increase safety.

1. Use a spud bar and check the ice in front of you as you walk. If the spud doesn't go through then neither will you. I've had a spud bar save my life more than once. This may not be super easy if on skis since you've already got poles in your hands and doing a scouting trip ahead of you is very tedious and time consuming and takes a lot of extra energy.

2. Do your homework. Ask around about known bad ice spots before heading out. Often times poor ice forms in the same area year after year and is often known to locals. That doesn't mean new spots don't form but at least you have info about known spots. Also study maps so identify pinch points, outlets, inlets, etc. When you approach these areas tread carefully.

3. Carry a set of ice picks around your neck to aid in climbing out of the water if you do go in. Ski poles can also work, just hold them down at the base and use the pointed end to dig into the ice.

4. Don't travel alone. Sure helps having a safety buddy.

NotLight
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09/28/2015 01:24PM  


Thanks nofish.

I wonder if ice picks give one a false sense of security. Still a good idea, but, when I went through some thin ice near shore last year (not a big deal), it was a reasonably big area of thin ice. Kind of hard to pull yourself out, without just breaking through the ice again as you pull yourself up/our of the water. Eventually maybe you get out, but you'll be pretty cold by then maybe.

So yeah, best not to be alone if possible, I suppose.

I will look for some ice rescue videos on the web. Maybe lose some weight :(





OldFingers57
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09/28/2015 03:30PM  
quote NotLight: "


Thanks nofish.


I wonder if ice picks give one a false sense of security. Still a good idea, but, when I went through some thin ice near shore last year (not a big deal), it was a reasonably big area of thin ice. Kind of hard to pull yourself out, without just breaking through the ice again as you pull yourself up/our of the water. Eventually maybe you get out, but you'll be pretty cold by then maybe.


So yeah, best not to be alone if possible, I suppose.


I will look for some ice rescue videos on the web. Maybe lose some weight :(





"


Yes that happens quite frequently where you will keep breaking thru till you hit some ice that is strong enough to support your weight. It can be very tiring even in an ice rescue suit. The best thing to do is go back the way you came and fell in from. As you know that ice is strong enough to support your weight till you hit the thin spot. Another thing I tell my Ice Rescuer students to do is to take the broken pieces and shove them under the ice that may be thin as it will help support more of their weight. Also when using Ice picks/awls. Don't try driving them into to the ice too hard as you can actually crack the ice by doing so. You want to set them somewhat and have them at an angle away from yourself. Plus don't go out an arms reach, do small increments so you are using your bicep muscles to pull you out more. Plus get your legs out behind you and do either a frog kick or a flutter kick to help push you up onto the ice.
09/30/2015 10:48AM  
My hubby and I went winter camping in February thinking the ice being 3 feet think would be safe. He was leading on a big lake and when accross a spring out in the middle we didn't know about. The ice gave way under his snow shoes but his snow shoes were able to hang on to the very edge and he was able to back up slowly and we went around the spring. The ice was 3 feet thick every where else.. sometimes you just don't know.. it is part of the risk
OldFingers57
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09/30/2015 12:08PM  
That's why I tell people that the only safe ice is at a hockey or ice skating arena in a building.
ZaraSp00k
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10/01/2015 01:30PM  
if you are using hiking/ski poles you can use them to be testing the area in front of you

I try to stay near shore, it is also usually less windy there and you see more wildlife. There have been a couple times I have been in danger of falling thru when by myself, makes you smarter for the next time. Caution and common sense are your best pieces of equipment.
 
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