Saturday, 8 December 2007

Submersion through ice at -30 degrees

In February this year I spent two weeks with my friend DR Heiko Schmidt at his home in Swedish Lapland. We had had several conversations concerning immersion through ice at the extreme temperatures encountered and factors affecting subsequent survival. We decided to undertake an experiment wearing clothes typical for the climate, to answer the question: “What happens if you break through the ice in harsh conditions?”

We wanted to establish whether it is possible to get out of the water, strip to woollen thermal underwear, and roll in the snow to absorb moisture from clothing, then walk and maintain activity, collect tinder and light a fire.


Because the ice was over one metre thick, we had to locate an area of open water which in this case was a fast running stream. The air temperature was -30 degrees (dry cold - at such a low temperature any moisture in the air has been converted to frost) with a light wind. Those involved were wearing clothing typical of dry cold conditions; woollen thermal underlayers and cotton outer. No assistance was provided to the individuals undertaking the experiment.

Test 1.

My parts of the experiment were to first walk into the water wearing three pairs of woollen socks, then walk through the snow for twenty minutes and maintain warm feet. Next wearing two layers of Ruskovilla merino wool thermals and my three pairs of woollen socks (I also had a cotton outer layer, typical outer wear in a dry cold climate) I entered into the ice water and submerged myself,

then exited the water and immediately removed my cotton outer layer (to prevent them potentially freezing to my body)

and rolled in the snow to absorb as much water from the wool as possible.

I then walked for twenty minutes in the forest to generate body heat.

Test 2.

Heiko then entered into the water wearing one layer of merino wool thermals and two pairs of socks. After emerging from the water Heiko walked for ten minutes and then collected fuel (birch bark and dead spruce branches) and lit a fire using a firesteel.


Although my outer layer of socks froze, my feet were warm and I was able to walk without discomfort. Following submersion, after an initial feeling of coldness, there was no shivering that would indicate a drop in core temperature. After rolling in snow and walking for two minutes, even though Heiko was only wearing one layer of thermals, we were both tolerably warm (still with no shivering). Wearing two layers, after twenty minutes body heat had increased and I felt warm and comfortable (apart from the genital area) considering the climate conditions.

Wearing one layer, Heiko found the experience bearable but not comfortable though again no shivering to indicate a drop in core temperature. After ten minutes walking, he had no problems collecting tinder and lighting fire with a firesteel. However, kneeling on snow with one layer of thermals was very cold leading to eventual numbness in the knees and feet.

When removing wet thermals and changing to dry clothes, both of us experienced shivering indicating the beginning of a drop in core temperature. After a few minutes in dry clothes we both felt ok.


Despite the harsh conditions of very cold water and an air temperature of -30 degrees there were no significant problems with major drop in body core temperature, indicated by lack of shivering. We both felt we could have continued much longer, however two layers of thermals appeared to be more beneficial than one. With outer clothing removed, we experienced no problems walking around for 20 minutes or collecting tinder and lighting a fire.

Wool is capable of absorbing up to 35 per cent water without feeling damp. After absorbing moisture, chemical reactions take place in its fibres releasing heat and as result making the fibre feel warm against the skin.
The water-repellant properties of wool are explained on the Ruskovilla website; “the surface layer of wool contains small micro pores which enable the fibre to let air through it. The pores are so small that water droplets cannot pass through the fibre's surface, but evaporated or molecular water (sweat) can pass through the surface pores. Therefore, wool is also somewhat water-repellent.”

If immersed for a longer period the outcome might be very different.

From our experience we would suggest;

  1. Insulation on the ground while lighting a fire such as spruce boughs may be beneficial
  2. Spare clothing carried in a waterproof bag makes a considerable difference
  3. Lacking snow, remove woollen under-layer, wring out and put back on again
  4. Remove outer layers quickly and lay out neatly in the snow to enable easier drying by the fire.
  5. Find shelter from the wind as soon as possible.

Heiko shortly after our experiment was completed.

No comments: