by CAMERON McPHERSON SMITH
copyright 1996
MOUNTAIN GEOGRAPHY AND WEATHER
Basic Mountain Geography
Figure XX illustrates the generic features of mountains. Various earthly forces will of course modify the specific cases, but the concepts remain the same worldwide. Get to know these features. In planning and route-finding knowing the relationships between features and types of terrain is essential to minimize objective dangers. For example, if you're in a white-out and descending a ridge, it would be better to know that a col can provide a retreat rather than following the ridge the whole way down. Mountain Weather
One of the themes of alpine climbing is that one must move quickly through 'windows' of good weather. Standard weather forecasts on radio and television are quite good for routes close to home, giving you an overall indication of whether it's worth heading out for the weekend or not. Once in the mountains, however (or in places where you can't get reports), the alpinist must be able to make at least basic weather predictions. These are often based on interpretation of atmospheric conditions - generally, clouds. Figure XX illustrates a number of cloud types and their general meaning. The basics are treated below, and you should consider these within the context of your mountains. Cumulus clouds forming en masse are bad news, often generating a spine-tingling chill if you're isolated high up. Cirrus clouds may be seen as a bad sign, bringing precipitation (rain, snow, sleet, hail, whatever) within 24 hours or so. Mist in the valleys and hollows below you shouldn't be a concern; it's a local phenomenon which portends little regarding major changes. Lenticular clouds, such as those often capping a peak, indicate high winds, which may be bad enough to stop you in your tracks, and/or could generate windslab avalanche conditions. Remember that mountain weather can change quickly and, to the puny human, violently. Also remember that mountain weather is basically cyclic; change, change, change, then start over again, or something to that effect. Get to know the cycles of weather in your range. Keep an eye on the weather as you make your approach. If it's clear and really cold at night, with a spectacular array of stars, perfect; unless it's going to be too hot the next day, increasing possibility of avalanche, rockfall and icefall. This is one reason why sometimes you'll plan to make the climb at night, or part of it anyway. If it's cloudy, warm and windy on the approach, you'll have to wait a bit (perhaps just keep moving) to see if things clear up later. Clouds effectively 'seal in' warm air, preventing it from escaping upwards (as warm air is wont to do). Heavy cloud, then, translates into more objective danger, preventing rock, ice and snow from freezing solidly into place. On the climb, keep an eye on the clouds and temperature. Monitor these and consider them in relation to your progress; where will you be when those clouds get here ? On the summit ? On the descent ? Back at your camp ? Ten feet higher than you are now ? Lightning You can often continue climbing through poor weather, thinking yourself rather heroic, though you may be blissfully unaware of the danger of lightning. Your best defenses are knowledge and adaptive cunning. The potential for lightning arrives with clouds (particularly large and heavy ones), in which electrical energy is generated. The charge may become too much for the insulator to handle (the insulator being air) and the energy is liberated in a flash, following the line of least insulating resistance. Sometimes this is upwards, sometimes it is laterally and sometimes it is downwards, which we humans most commonly observe. If you observe signs of huge power generation in the clouds above - crackling static noises all about you, a corona of light shimmering on ice tools and other hardware, the smell of ionized (charged) air - called ozone - beware. You are in danger. On most climbs you will have little latitude for seeking shelter. Figure XX illustrates some features you may encounter which are, respectively, suicidal, dangerous, decent and relatively safe. Good luck. If your 'luck' runs out, and someone is struck, you have a job on your hands. Better to have retreated at the signs of bad weather. You will now have to administer first aid; let's hope you spent some time training and know the principles.
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