This summer, many hikers and campers will head to the mountains, hoping to recharge their souls and to escape the heat of the lowlands. For their own health and safety, it is important that they are familiar with the challenges and fickle nature of mountain weather.
All other factors remaining equal, the temperature will fall 3.5 degrees F for every 1000 feet of elevation gain. In addition, high winds are common along mountain slopes, adding to the chilling effect of the altitude. On the other hand, the thin atmosphere increases direct warming from the sun and reduces protection from UV radiation. For all of these reasons, it is best to wear layers of clothing (including a waterproof parka) that can be adjusted through the course of the day; while staying warm is important, sweating will actually increase your risk of hypothermia should clouds or storms roll in. Obviously, sun screen and UV-protective sun glasses are also important equipment for any mountain excursion.
During the night, cold air sinks into the mountain valleys and onto the adjacent plains; come morning, the flow reverses as the lowlands begin to warm up. This rising air, which cools and saturates as it moves up the slope, sets the stage for thunderstorm development above the mountain ridges. These storms usually form by early afternoon and those who plan to hike above timberline should retreat from the open tundra by noon; lightening is a significant threat to those who enter the alpine landscape. Finally, the thin air and high altitude augment radiation of heat, producing a dramatic fall in temperature after sunset; a tent, a quality sleeping bag, warm, layered clothing (including a sock hat) and high-energy food are essential to prevent hypothermia.
