going through the ice

[sleeping bear]

This weekend I had my first experience with going through ice in the winter. I'm curious about why.

This weekend a friend and I camped near a lake quite far from any main roads. We planned to cross a frozen lake then up a channel and across another lake. We had heard that someone went through the ice on lake #1 last weekend, but I was skeptical. Two weekends ago I went ice fishing at a different lake nearby that had cars parked next to each other on the middle. I didn't have too many doubts about the thickness of the lake ice. When we got to lake #1 we shovelled down to the ice and I bent my metal shovel trying to chip at it and see how thick it was. We assumed if it would bend my shovel it would hold us. When we got to the channel we could clearly see where someone on skis had gone through the ice (maybe a week ago) so we headed for the bank. As we followed the chanel we could see other places where it looked like skiers had gone through. When we could see lake #2 I headed across the channel. My first step off the bank went right through. I fell and realized what had happened. I floundered around in what was not ice breaking, but about 6 inches of slush. I manged to roll/swim close enough to shore that my friend helped pull me out. Thanks to gaitors and snowpants I didn't get very wet. I was shaken but we continued on after I collected myself. The ice on Lake #2 supported out travel without question.

So, why wasn't the channel frozen? I knew I had gone in not because I could feel the water but because I could smell it. It smelled swampy. Is it possible that enough decomposing matter in shallow stationary water could keep it warm enough to not freeze? This is the only logical explantion I've been able to come to. It's been well below 20 degrees here consistently for the last month, with about a week well below zero. Any thoughts?

 

[Lawn Sale]

It was due to either currents or springs. I almost went through while skiing across Moosehead Lake here in Maine one February. It was -5° without the wind and there was over 48" where people were ice fishing. It was a spring hole that never allowed the ice to form properly.

Decomposing matter at those temps could not produce enough oxygen to keep the ice from forming properly in that instance. The water temperature will hold more oxygen and less is transferred due to reduced biological respiration. Many plant species hibernate in the winter and do not reform until wamer water temperatures, around 10°C. I know of many swamps that freeze over fine.

 

[Grumpy]

I would be inclined to blame the weak ice on currents or springs -- moving water -- in the channel. Also, fluctuating water levels in stream channels can leave unsupported and readily broken sheets of ice.

G.

 

[DougPaul]

I would be inclined to blame the weak ice on currents or springs -- moving water -- in the channel. Also, fluctuating water levels in stream channels can leave unsupported and readily broken sheets of ice.

Agreed.

I have broken through on Lower Greely Pond over near the NW corner. Went in about 2 inches into mud. Rolled to the side and the ice supported me. (Trade-off: roll to the side risking getting one's body wet vs standing up and hoping that one's feet hit bottom before one's body goes in.)

Be particularly careful near inlets and outlets. But you cannot see the springs away from the edge... Tap the ice with your poles to make sure it sounds solid. Snow (insulator) on top of the ice can weaken the ice.

Good info on falling through and what to do: http://www.umanitoba.ca/faculties/physed/research/people/giesbrecht.shtml. Prof Giesbrecht goes around demoing the effects by jumping into vats of ice water while they measure his body temp...

Doug

 

[Stan]

I would be inclined to blame the weak ice on currents or springs -- moving water -- in the channel. Also, fluctuating water levels in stream channels can leave unsupported and readily broken sheets of ice. G.

That seems to cover the causes in a nutshell and it reinforces the reasons why I've broken through on at least three occasions on snowshoes, and I don't weigh that much but there's no sense in getting in any deeper over that topic.

All three breakthroughs were near the edges of ponds. One near an inlet (flowing) where a couple feet of snow cover masked bare water. I avoided hitting the water but hugged the shore quite dearly after that.

The others were in marshy areas, one near an outlet, where marsh grass protruded from the snow. They were more likely due to the fluctuating levels but deep enough to reinforce the fact that wet wool still keeps your feet warm ... I continued with the hikes with the notion that I would change into dry socks if my feet started to get cold and that didn't happen.

All incidents occurred on ponds where there was no other human activity and it is always my habit to skirt the edges no matter how inviting the straight line across the middle.

 

[grouseking]

I fell in the outlet at Upper Greeley Pond about two years ago. We walked across the middle of the pond on solid ice and when we got to the end, I was standing on top of at least 4-5 feet of drifted snow. Then, without warning, I went under and had snow up to my chest, and could feel my boot getting wet. I tried to pull myself out and then my other foot went in! If I had been alone it would have been dangerous. My friend has pics of me getting pulled out by a very strong buddy of ours. (To pull out a 280 lb person stuck in 5 feet of snow, takes talent!) Suffice to say I will never, ever go near an outlet again.

grouseking

 

[erugs]

Brian and I were cross country skiing on Saddleback Lake yesterday and became uncomfortable when we heard several sounds of "whomp" beneath us. Brian scooped snow, digging down about two feet, whereupon he encountered slush. We decided to turn around head head for land-based trails instead. It seems as though it's been cold enough that the lake should have been frozen solid. I don't think falling in would have been very much fun.

 

[Snohm Eizer]

I went through at Flowed Lands a couple years ago. It was after a warm spell had sent all the runoff on top of the frozen lake making a deep slush on top of the ice. Then that was covered by a fresh layer of powder. I was on a solo hike across the lake, all of a sudden it felt like jello, and I dropped.

Your situation sounds like (as others already said) springs. Springwater is amazing stuff - I run it in all my cars because it doesn't freeze

 

[Nessmuk]

I would be inclined to blame the weak ice on currents or springs -- moving water -- in the channel. Also, fluctuating water levels in stream channels can leave unsupported and readily broken sheets of ice.

G.

Simply thinking about the physics of the matter will help understanding of why this is so. Most substances in nature contract as they get colder, making them more dense as the temperature drops. This is true of water, until it begins to do something strange that most other substances don't do. At about 4 degrees C water reaches it's maximum density, then it actually begins to expand as the molecules line themselves up to become ice crystals. In a calm lake or pond water will naturally tend to stratify into layers of differing temperatures, warmer on top, colder on the bottom until it gets to 4 degrees C. While still in liquid state, this colder than 4 degree C water begins to expand and rise above of the denser slighter warmer water. This very near freezing water is now the top layer, where is soon freezes (expanding even more) into floating ice at 0 degrees C.

Now imagine a slight current caused by a bottom entering spring or small entering stream with water of differing temperature. It doesn't take much movement of swirling turbulence to upset the stratification, causing the denser but warmer water to swirl up into the previously colder top layer. Freezing is delayed or prevented altogether. It is not uncommon to be walking on a pond over a foot or two of solid ice, where a short distance away there may be very thin ice or even pockets of open water.

This also explains the phenomenon of ponds "turning over" in the spring, when the top layer of newly melted warming water sinks in mass, forcing the bottom layers to rise, stirring up nutrirents from the bottom.

Most liquids do not freeze in this manner. They become uniformly denser and freeze from the bottom up. Just imagine how different things would be if water behaved this way.

Just to put emphasis on an item in the web page DougPaul references above, everyone should be sure to view falling through the ice survival techniques or its high-res version.

 

[Quack]

Most liquids do not freeze in this manner. They become uniformly denser and freeze from the bottom up. Just imagine how different things would be if water behaved this way.

It would make Ice Fishing really easy...

 

[KayakDan]

I had an interesting "going through the ice" experience myself on Saturday. We were snowshoeing the South Pond Loop at Savoy Mountain,and dedcided to bushwack across the Tyler Swamp towards the summit. At one point I was standing on about a foot of windpacked powder,and suddenly dropped about 3 feet. I heard ice breaking,and assumed the worst,but when I stopped,I was standing in a dry hole with ice at the waist level. Very strange!
Seems that the swamp froze over,and the water table must have dropped with the lack of precipitation,leaving a frozen swamp,with no water under the ice.
With that incident,my wife promptly did a 180o back to the trail,and we went the long,but dry way. She wasn't keen on 'wacking the swamp,and that incident didn't convince her.

 

[DougPaul]

Springwater is amazing stuff - I run it in all my cars because it doesn't freeze

The only problem is the long hose because you have to keep it flowing...

Doug

 

[Woody]

Sleeping Bear,

I'm just glad you didn't get hurt going through the ice. I think climbing ice is probably safer than walking across it

Woody

 

[Andrew]

It seems that changing snow depths also influence the other factors mentioned.
I've noticed times during very cold periods where a body of water was well frozen, but upon returning a few days later with new snow cover and no major change from the cold temps, slushy areas form where there was walkable ice. I always figured that the snow insulated the ice layer to a stable temperature that was giving the other influences with warm water movement under the ice a chance. It also seems that a hole that forms in the ice can serve to 'wick' water up out of the snow and create a soaked sub layer over seemingly dry snow. As the area becomes saturated the ice can depress and cause more water to flow and soak in, creating those situations where you know the ice was thick enough, but there is no mistaking that you are skimming just above a whole bunch of water just under the snow!

 

[Nessmuk]

It seems that changing snow depths also influence the other factors mentioned....
It also seems that a hole that forms in the ice can serve to 'wick' water up out of the snow and create a soaked sub layer over seemingly dry snow. As the area becomes saturated the ice can depress and cause more water to flow and soak in, creating those situations where you know the ice was thick enough, but there is no mistaking that you are skimming just above a whole bunch of water just under the snow!

Many times there is a very wet slush layer just above solid ice, perhaps under a few inches of insulating snow, perhaps not. When you think about it, the water level may change by a small amount for many reasons, such as increased inflow by partial melting upstream, blockage of the outlet by ice buildup, or whatever. Rising water has to go somewhere. It will either crack the ice as the ice tries to float above, or (more likely) water will seep through weak areas and lie on top of the less vertically mobile ice. Once it is there it remains as slush even if the general water level drops again or until prolonged cold temps freeze it solid. It can be disconcerting to be walking on sloppy slush while hoping that the solid layer underneath is thick enough.

 

[sleeping bear]

There was slush on top of ice on the lakes near the channels. Must have been water from the channel rising above the level of the ice on the lake. There wasn another spot near the shore with slush on top of ice.

I've always been pretty freaked out about walking on ice, just the thought of plunging into an icy lake makes me midly hypothermic. Saturday's experience has given me even greater fear and respect for frozen water. On that hike I had also opted not to bring my ski poles which were back at camp. If I had those I could have tested the channel before stepping. The whole expereince has me rethinking how things are packed in my pack too. Gaitors helped keep the water out and if it wasn't for full length zippers on my pants I may have even stayed dry. It was not the most fun experience and I count myself lucky to have learned such a big lesson without big consequences.

 

[spider solo]

It is usually the stream crossings that give me trepidaton...more so if I'm travelling alone.
I have broken through with snowshoes on, and have had a real difficult time getiing my foot free without it further dragging me in.esp near steep embankments where there is nothing to hold onto.

Swamps, beaver ponds,, and outlets are very deceptive with lots of weak spots.
A couple of years ago I went just a few feet off trail to look a lttle closer at the pond by Greenleaf Hut. Within the 1st few steps my foot went under...I thought "this is okay there's only a few inches of water.
Yet I couldn't free up my foot with the snowshoes on. With one foot on semi solid ground I bent down to see if that would help. Now I have one foot in the water and am kneeling with the other.
No luck ..and I'm a heck of a lot shorter than when standing.
Sure enough, I am almost prone, partly in the water before I can wriggle myself free.
That few inches of water takes on a whole different perspective when your lying beside it and are now...about 18 inches tall.

Glad your ok, water is tricky stuff esp. in the winter where you not only have the depth of the water to deal with as well as the depth of the snow above it.

 

[lattinhill]

And once you do manage to get safely out of the water and start walking through the snow in wet snowshoes.....
Been there & done that !

Dave

 

[the starchild]

Yet I couldn't free up my foot with the snowshoes on.

yikes! this happened to me two weekends ago in the flume except i didn't get wet, my foot and snowshoe were just dangling in nothingness. when i could finally get my foot and snowshoe back out of the hole, we peered down 4 or 5 feet to the running water below. not good!

has anyone ever fallen in like that and been swept under? that's all i kept thinking about. uuggghhh!

 

[RoySwkr]

I've fallen through the ice numerous times, usually on early spring canoe trips where I shift my weight over the canoe before going in very deep.

Remember that while a snowmobile or ATV may weigh more than a person it also has more bearing area, particularly someone wearing crampons who may be applying a pressure of 1000 psi to the actual contact area. I remember once on Carrigain when my sister and I walked safely across a brook but a guy following in Sherpa snowshoes broke through - apparently the crampons concentrated his weight more.

yikes! this happened to me two weekends ago in the flume except i didn't get wet, my foot and snowshoe were just dangling in nothingness. when i could finally get my foot and snowshoe back out of the hole, we peered down 4 or 5 feet to the running water below. not good!

has anyone ever fallen in like that and been swept under? that's all i kept thinking about. uuggghhh!

I think it was an old Waterman column where they talked about a guy who liked to do solo winter backpacks in remote areas, he fell through hollow ice like you describe but landed dry, he was in some sort of hollow chamber and no way could he reach back to the hole he fell through. Yes, this was New England not a glacier somewhere.

Many times there is a very wet slush layer just above solid ice, perhaps under a few inches of insulating snow, perhaps not. When you think about it, the water level may change by a small amount for many reasons, such as increased inflow by partial melting upstream, blockage of the outlet by ice buildup, or whatever.

I've seen it where a second ice crust forms on top of the slush layer. If you break through that ice you land in the slush and hope the second layer holds.