I’m back from my last winter walking trip with the school (to the Lakes), and it was quite definitely one of the best trips I have been on! Here are some things I picked up on when I was there – hopefully this will be useful for whenever I next go hiking in winter.
We noticed this rather interesting phenomenon on the first day on Skiddaw (931 m):
Apparently the reason for this is that as the wind blows across an object, little bits of water vapour condense on the surface of the object. If it’s cold enough (which it was) the water freezes immediately on the side of the object the wind is blowing. If this goes on for long enough with a constant wind direction, you get massive ice chunks several inches long pointing in the direction of the wind. Cool huh?
Apparently the Gold DoE guys were advised that “batteries run out faster when cold”, and therefore that they should put electronic devices in their pockets to keep them warm. A little thought reveals this as a half-truth; batteries produce a voltage due to an electrochemical reaction (cf. my inorganic chemistry notes!) and a reduction of temperature reduces the rate of reaction, reducing the size of the voltage. So it is true that batteries perform worse in the cold and that one can increase their performance by heating them up; however since the reaction is taking place slower, they are actually being used up more slowly so I guess it’s inaccurate to say they ‘run out’ faster (their output voltage falls to most devices’ threshold faster but they don’t lose energy faster, so I guess whether they ‘run out’ faster is interpretation-dependent).
I thought the effect would be pretty minimal, but considering it was about -5°C (with wind-chill bringing it down to below -20°C), it wasn’t all that surprising I went through 3 packs of batteries on the first walk! Rechargeable batteries are extremely poor in the cold, partly because they start off below 1.5V, and probably also to do with greater sensitivity of rate constants to temperature etc. (stuff we haven’t yet done in chemistry). My Duracell Alkaline batteries were also pretty rubbish; the only thing that lasted long in the cold were GP “Super” Alkaline batteries (0% Hg/Cd) given to me by Dave. They lasted the whole of the second day.
After this trip I won’t say a word against these things ever again for a very good reason: there’s only one (good) way of going down an icy slope!
These are unbelievably useful. The ability to sit down and sip warm tea at the top of a mountain where spit goes ‘chink’ (ok it wasn’t *that* cold) is really quite something. Plus don’t use a camelbak system. Really don’t.
Buffs / Balaclavas
Wind-chill is the main problem when walking across ridges, and scarves simply don’t cut it when it comes to face-protection. Mine kept getting tangled and falling off my face and directing my breath up onto my glasses where the condensation just froze onto the lenses making seeing rather difficult! So yeah – I’m getting a proper buff for next time. Also, speaking of wind-chill, ski-goggles are also useful even when not skiing.