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Ice Safety; on lake ice, & on river ice.

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  • Ice Safety; on lake ice, & on river ice.

    My goal in this thread is sharing ideas and having a discussion.

    I hope you will add your thoughts, please.

    Not many of us fall through thin ice while on a trek, but it does happen occasionally and it results in a anything from a boot full of water to death. So, I think of the incidence of falling through ice as being low, and the consequences as being potentially huge.

    Certainly most people I know and most people I trek with are not confident in their comfort judging ice conditions or ice safety. This is understandable because even with thorough theoretical knowledge, application in the field is often high risk. Field situations require the consideration and assessment of many variable factors.

    What do you think about the statements above?

    What do you think about this statement?

    Ice is always getting thicker or thinner.
    On lakes this change can be slow. On rivers this change can be fast.
    But, ice thickness and strength is always changing.
    Last edited by Undersky; 01-20-2021, 01:50 PM.

  • #2
    Here are my statements
    No ice is safe. if it is not tracks on snow on unknown water body be ready to get wet.
    it is pain to walk even with one boot full of water even for half of mile unless you are Leonardo de Caprio
    it is very hard to dry soaked outwear and foowear till you get tent up and stove running


    • #3
      Originally posted by Undersky View Post
      My goal in this thread is sharing ideas and having a discussion.
      What do you think about this statement?

      Ice is always getting thicker or thinner.
      On lakes this change can be slow. On rivers this change can be fast.
      But, ice thickness and strength is always changing.
      Good info to keep in mind. I'd also add that inlets and outlets to lakes can also have fast changing conditions since it's more like a river than a lake in those areas.


      • Undersky
        Undersky commented
        Editing a comment
        Hey SD_Motak,

        Good catch! Perhaps it should read like this:

        Ice is always getting thicker or thinner.
        On still water this change can be slow. On moving water this change can be fast.
        But, ice thickness and strength is always changing.

    • #4
      No objections to what you wrote. I do a fair bit of solo ice travel in the back-country so I think a lot about ice safety. Here are the things I do or have found helpful
      • This site has a ton of insights into ice, how it behaves and strategies for making travel safer.
      • I carry a ice spike and I test the ice frequently when I am unsure of it's condition. You can see my ice spike design in this forum thread.
      • I have a small backpack I wear when on the ice. It has large air tight bags of heavy fleece clothing; pullover, pants, and mittens. This helps in two way.
        • I have found I lose use of my fingers pretty quickly after immersion so all of this clothing can be pulled on. If I am able I will strip before putting it on, great, but I it can also be pulled over wet clothes.
        • The trapped air in the bags turn the backpack into a float if I should fall in. I have added a small rope that loops under one leg to keep the bag from floating up.
      • I took a class intended for people who speed time working on ice that included how to read ice, how to self rescue, and actually jumping into the water and performing a self rescue. It was not a lot of fun but I learned a ton. That is why I have pull-on clothing in my backpack, I found I couldn't mesh zippers after getting out. Here is the class I took.
      • I have ice spikes(a.k.a Ice claws) that I wear around my neck in easy reach (not in a closed pocket or under a layer) when traveling on ice. Here is some more info about these
      • Before I go somewhere I gather as much data as I can from this seasons weather history for that area, what snowmobile trails are open, web cams from places nearby that give a peek on conditions, and recent satellite photography of the area. Ice fisherman are a great resource if you know any since they always know how thick the ice is.
      • Of course, I give a wide berth to any location where water is moving in an out of a body or it's flow speeds up due to a constriction. I find the ice in the center of small lakes generally more consistent and reliable.
      Last edited by timdaman; 01-22-2021, 11:15 PM. Reason: Corrected a bunch of typos


      • #5
        Your experience, training, awareness and thoughtfulness about ice travel is obvious, Timdaman! The people who travel with you on ice are safer than they would otherwise be. Thank you for sharing. Thanks for the links, too!


        • #6
          On the old winter trekking website was a link to a site with lots of information about ice and ice safety. I think it was mostly targeted at ice yachting but it had lots of information about how week spots for in ice and what hazards to look for. Be good to find that site again.

          the times I have broken through it’s always been on small creeks, often where the water has dropped, leaving an air pocket below a thin layer of ice, and on beaver ponds where there is lots of organic decomposition happening below.


          • #7
            Think it was this site.


            • #8
              "No ice, is safe ice" is a great mantra to follow!!



              • #9
                Lonelake, If you mean that not being on ice at all is the safest approach, I cannot argue in the least with your mantra. After all, when I was a wide-ranging pre-teen who loved roaming all day in the bush my mother's mantra was "you never drown on Lac St. Clair so long you stay on shore". I believe these two approaches are one-in-the-same in principle, at least.

                If, instead, you mean that it is safest to be on ice as little as possible, I certainly agree with that, too.

                But, here in Manitoba there are far fewer Boreal forest snow camping routes without lake travel than there are routes that require travel over ice.

                On big lakes where the snow is blown away, January ice is often 1.3 metre (4.25feet) or more thick. Even on rivers with currents running at 4km/hr (2.5 miles/hr) the ice is 60 cm (24 inches) thick right now.

                So, while it is true that it is definitely safer to not travel on ice at all, perhaps it is also true that a full understanding of ice in all its strengths, weaknesses, and changeability, can allow a snow walker to have a better winter experience, in some locales.
                Last edited by Undersky; 01-28-2021, 07:41 AM.


                • #10
                  So, while it is true that it is definitely safer to not travel on ice at all, perhaps it is also true that a full understanding of ice in all its strengths, weaknesses, and changeability, can allow a snow walker to have a better winter experience, in some locales.
                  I agree.

                  When I was about 8 years old I remember walking across a frozen lake for the first time. The ice was cracking and booming in the cold air and I was nervous as all get out. When I saw an ice fisher driving across in a pickup I had my first clue as to how strong ice could be.

                  In recent years I've built several floating ice air strips in the arctic, both on freshwater ice and on sea ice. I have to admit that I still get nervous running a D7 dozer on the ice, but that doesn't happen before I've done lots of ice profiling. It's amazing how much difference there can be in ice thickness over a span of a few feet on a lake. There are strange and mysterious things that go on under the ice.

                  It's quite a feeling to watch the first 125,000 lb Hercules make the landing.


                  • #11
                    Bushman, do you mind telling us what ice thickness you have to find before you are comfortable saying, "Good to go!" for a D7?

                    I know that the huge cats run around 150,000 lbs. but what weight is a D7, do you think?

                    125,000 lbs is a heavy aircraft, and having the ice fail in any way is obviously just not acceptable.

                    I have a vivid visual and body memory of a pressure wave on a thick lake ice road. That road used to run across just north of the narrows on Lake Winnipeg. That wave was definitely visible and you could feel it pass (or maybe I imagined I could only feel it because I could see it?) The loaded semi was moving at maybe 25kmph (18 mph) and there was a very long, low bulge or wave in the ice well out ahead of him. The low wave was extra visible because I was looking toward the sun, so a small change in the plane of the cleared ice showed as a big change in appearance.


                    • #12
                      Undersky, the D7 I've been using has a ripper attachment which brings the weight to 29,500 kg (65,000 lbs). As for ice thickness, it all depends on the level of risk you're willing to live with. We use Gold's Formula to calculate the ice needed at different risk levels. For a low risk level the D7 would need 95 cm of lake ice. River ice and sea ice are different calculations. For a tolerable risk it's 90 cm. Moderate risk is 80 cm and substantial risk is 75 cm. We generally go with a tolerable risk so for the 7 it's 90 cm or 35 inches.

                      As far as ice needed for the Herc, it really depends on what the captain is comfortable with. Gold's Formula would indicate 130 cm (50 inches). When First Air still had Hercs they wanted 60 inches but Lynden from Alaska is happy with 48 inches.

                      When I sign off on the strip before the first flight I certify ice thickness, quality and amount of freeboard at hundreds of stations and the captain makes a decision based on my numbers.

                      Watching ice waves is pretty cool. The truckers are usually limited to 10 kmh when approaching portages on land since going faster can cause the ice wave proceeding them to break up the ice on shore. Before building the floating ice air strips we do a bathymetry survey to make sure there are no spots where the water is less than 5 metres deep as the wave travelling over shallow water can cause major problems with ice breakage.


                      • #13
                        When i was flying HS 748 and ATR's in the arctic we liked between 45 and 50 inches. ATR-72 had a landing weight of 46,000 lbs, so a light weight compared to the Herc.

                        As for ice travel, man there is just something that tells you sometimes its not safe. Some kind of prehistoric instinct. When I get that feeling I tread lightly.

                        I just came back a few days ago from a 5 day solo ski doo trip in NE Manitoba and just over the border into Ontario. Lake ice was average about 12 - 14 inches. And one lake at a narrows I could tell the ice was very thin. Although this lake had one decent stream draining, there was no appreciatable inflow, however there must have been current in the narrows. I walked over to investigate and promptly ended up breaking through into the shallows about 10 feet from shore. Felt pretty silly, as my instinct told me it was unsafe. But like a moth to a flame. I suppose better a boot than the whole machine.

                        A funny story about prehistoric insticts. I once found myself in the darkened cargo hold of a ATR 42 aircraft with a Polar bear in a cage. As I passed by the cage in the dark it made low menacing bear noise..... some small ancient part of my brain knew instantly I was in a dark cave with a bear and I went into full fledged flight mode!


                        • Undersky
                          Undersky commented
                          Editing a comment
                          Without question being that close to a polar bear would drive me into brainstem thinking! And then to have to fly that plane with the bear as a passenger?!!

                      • #14
                        Thank you for the detail, Bushedbushman!

                        35 + inches seems to be the minimum for that medium-sized cat + ripper. I am going to learn about "Gold's Formula" - that is new to me.

                        Yes, the ice wave visual is one that sticks hard in your brain! "Phenomenal" is an apt descriptor for the average person to use when describing a long, low ice wave coming toward them on very thick ice. Undoubtedly ice waves would become more commonplace for someone like yourself, but I bet you still take note when you feel one!

                        FlytoCamp, it is neat that you mention the thinner ice at a lake narrows. In my experience these spots are always suspect, even in more typical MB winters when the ice is pretty bombproof elsewhere.

                        One spot that often exhibits that type of dangerous ice through the whole winter is a narrows on the SE bay of Davidson L. As you'll likely already know, Davidson L. straddles the MB / ONT border at the East end of Hwy 315. The narrows I speak of is 1.7 km East of the border and about 1 km South of the Werner Lake Rd. The creek flowing into the extreme South end of this bay is but a trickle at this time of year, and although the narrows is split by an islet, there is lots of water depth and width (area of cross-section) within the channel at the narrows.

                        Interested, I snooped around on one trip just as you did and found the the ice over the deep water part of the channel was thick (>30 cm), but the ice over the shallower parts of the channel (such as on the shoulders of the little islet, and close to the mainland East shore) was too thin to walk on.

                        So, why is there thin ice if there is virtually zero current? My best guess is that with prevailing N-to-S or S-to-N winds, lake water from the basin on the north side of the narrows is seiched through the narrows into the South basin, and vise-versa. Changing atmospheric pressure pushes downward more on one basin than on the other, pushing water through toward the lower pressure side. Because the basins are fairly small, and the ice cover is unyielding, it may be that as soon as the wind gust that pushed water through in one direction is over, gravity pulls that water right back through the narrows again. Perhaps these water movement events occur many times per hour during a windy day. Each time, relatively warm water from the deeper parts of the adjacent basins surges through and retards freezing, or may even melts ice where the flow rate is magnified over shoals of bedrock.

                        (Obviously I've got to expand my horizons to get a life!! But, I find this stuff interesting, and understanding improves safety and fun.)

                        Whatever the reason for the thinner ice, a lake narrows is always a place to be especially cautious.


                        • #15
                          Lake travel on a crisp day with a nice wind-packed crust is the most magnificent thing. But then there's the always-present danger. I've seen lake ice be 24" in one part of a lake, and completely open at the narrows...

                          Meanwhile, in Windsor:

                          For what it's worth, I hear that the perch fishing was fantastic the day before. Not worth it though.