The Effect Of Cold Weather..., ..putting an author to the test

[phantasm]

There is one fatal problem in the experiments about cold etc... What matters the most is are you used to being at cold or not.

As a fact an adult in normal physical condition (not obese, decent fitness) can do some very extreme sounding things. All it takes is getting used to cold. All these are proven facts from experience of myself or close friends of mine and as such are reliable. (Yes, I am a Finn.)

1) Walk 15 minutes to a hole in ice with just a towel and sandals, go swimming for a couple minutes (critical - do not swim more than 5 minutes or you risk hypothermia!) and then walk back. Can be done at -20 C just fine. No adverse effects etc. Doesn't even feel cold or anything really.

2) Slowly walking around taking a dog out with shorts, t-shirt and boots for times of at least an hour in whatever weather the winter gives in South Finland. That includes temperatures of as low as -30 C, nasty snowstorms (worst at about 0 C when it is actually sleet storm).


All it takes is getting used to it. You don't really notice it being that cold at all if you take your dog out every day. But if you take a month pause at the time when it is getting colder, it is a whole another thing. Or going out normally in warm clothing and then suddenly changing to light clothing.

And yes, that means that you do not need to move around to stay warm. Body can make heat at levels higher than physical exercise alone can make. It will take a whole lot of energy, so you will need to eat a lot more, but it can be done.

And one critical thing is not to sweat when it is cold... At -30 C or colder, you are at real risk of dying if you sweat - no matter the clothing.


As things really extreme that do require a lot of training, from reliable sources... Some monks can sleep outside at -20 C with just a very thin bed-sheet around body. The dry (this is crucial) sheet gives just enough separation from the snow that skin can stay without frostbites and for the snow not to melt (given low enough temperature). Another nice thing comes from being able to control skin temperature (flow of blood near skin) is to be able to dry out clothes at will. Just wearing wet clothes and allowing skin temperature to raise to body temperature will cause the wet clothes to start steaming. This requires cold air, but many know the steaming thing from urinating outside when it is cold - the urine will cause steam around it.


As for hypothermia... Yes, it causes weird sense of being warm etc... But one can learn to sense the false feeling from hypothermia and know when the situation is really bad. It is actually very accurate measurement of 'critical danger'. And as for URW... We can safely assume people back then living in the far north will know about the extremes cold weather can do. And as such we can assume every child is taught about the false feeling and the danger of such. And once one has hypothermia, it is crucial not to do excessive physical exercise or the cold blood will get to heart causing it to stop.


The only thing I lack knowledge of, is the affect of not having at least light boots on prolonged exposure to snow/ice. For short time the feet will really feel terrible etc... And as the skin temperature is low, any sharp things of ice will cause cuts. Therefore, it is of utmost importance to wear at least some light boots. Or even socks do enough.


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Summary:
- Almost any temperatures can be survived in almost any clothing without frostbites just fine as long as one is used to the level of clothing.
- Prolonged swimming in cold will kill - but you do see signs of hypothermia before it is too late.
- Sleet storm is worse than snowstorm. Sleet without wind is just annoying. Snow without wind doesn't matter.
- Wind has little affect IF you are clothed with wind-proof clothes such as leather or fur. Wind has huge effect for unprotected skin.


Therefore, for URW, there needs to be a system to track the level of getting used to current temperature. And it needs to change slowly. 2 weeks inside without a moment outside will not significantly affect. A month will significantly affect. As such, being outside often will cause the getting used to current temperature to be effectively always 'ideal'. There can be around zero C for few weeks and then suddenly -20 C, but as you have gotten used to the cold before the few weeks of zero C, you are still properly used to cold as the zero C is half the way from warm inside temp and -20 C.

Even with quite random temperatures around the time it is getting colder, there won't be significant problems getting used to the cold. It can be 10 C for a month, then suddenly go 0 C, but it doesn't matter. Generally the temperature just won't drop too fast to not to get used to if you do outside almost daily.

The reasons for this is that you will get used to cold much faster than you will lose the ability to stay comfortably at cold. And mild amount of colder than one is used to is not even enough to really cause any moral problems.


I don't have exact numbers for the amount of extra food one needs in extreme cold temperatures, but I recall it is around 5 times as much as normally. Therefore, I suggest around the following scale:

No wind:
+30 C - delta 0: 1 times normal
-30 C - delta 60: 5 times normal

As for wind, use normal tables when no clothing at all. (Educated guess) Halve affect with light non-wind-proof clothing, quarter with heavy. Quarter with light wind-proof clothing, 1/8 with heavy wind-proof clothing. Average over body. Doesn't matter if some parts are exposed unless there is sweating.

As for sweating, unless it is raining or non-winter night (in which case relative humidity is 100% and doesn't matter), sweating amount*(double wind affect and halve clothing affect). With sweating amount being float between 0 and 1.

As for 'effective temp' under -30 C... I don't know how fast frostbites and hypothermia really comes, so can't help there.

Anyway, as last critical part... There needs to be affect on condition of clothing instead of perfect until broken. Otherwise getting used to temp part will fail badly. And one should be able to repair at least fur/leather clothing.

Edit:
Oh yea... When not gotten used to coldness. Moral problems when not moving enough (low concentration etc. Tasks will take longer.) and easier frostbites. But doesn't matter much for serious injuries.

[Rina_Inverse]

humidity actually is a great deal of a matter when comes to heat and cold, more humidity there is more the heat and-or cold is felt, dry cold and dry heat are felt alot less humid ones are devastating.

[phantasm]

Yes, that goes for relatively high temperatures. But considering situations of very cold, the humidity you feel will be a lot lower. 100 % relative humidity at -10 C goes to 12 % at 20 C. So, if your outer skin temperature was 20 C, you would feel -10 C with relative humidity of 100 % as very dry air of 12 % relative humidity. As such, at cold temperatures the humidity plays very little role.

As for same reasons, sweating in cold is bad as the moisture will evaporate very easily causing excessive coldness. In temperatures of around -50 C, if your clothing is slightly too hot causing you to sweat, you will be in great risk of dying.