FORECASTING MOUNTAIN WEATHER is just as much an art as it is science. Complex terrain, massive elevation changes, and a wide variation between day and night temperatures complicate accurate prediction. The big storms synonymous with high-elevation landscapes are based on a few basic principles. The higher you go, the colder the temps and the thinner the air. That sparse air retains less warmth, and overall mountains are wetter than flatlands. Then throw in the fact that many ranges are the first large feature that incoming moisture from the ocean meets, and you’ve got a recipe for volatile and unexpected weather patterns.
Illness is the number one cause of failure on an expedition, but weather is a close second, and it’s not always in the form of a massive snow dump or rainstorm. Rain or running melt water can derail major rock missions, while hot weather combined with south-facing snow or serac-filled icefields can create a deadly scenario. Then there’s the weather effect on your multiple legs of travel. Flights get delayed, and roads get washed out. Beyond objective hazards and time delays, the conditions might make your climb impossible. It’s best to be mentally prepared for these disappointing situations, going in with low expectations. You can’t change the weather, but you can change your attitude. Weather predictions will never be 100% accurate, but here are few tools and pointers from experts Garrett Madison and Luke Smithwick to prepare you for the most capricious element of your expedition.
If climbing in an obscure area, Luke Smithwick suggests adding at least a week to your itinerary to give time to observe the weather and have extra time if a storm rolls through basecamp. He says, “Having time is key because you're really working with what you see in the sky. I observe in shifts, so I'm always watching all these subtle variations. I'm very much into forecasting and deciding things myself without support from the outside because in the places I go, the outside doesn't really know.”
He suggests to read up on general weather patterns on the web, in guidebooks, and, if possible, seek advice. “In many of the places I visit, the weather varies so much from location to location because there’s always a subtle, local effect. If you're going to 8,000 meters, forecasters are pretty good at predicting windows of good weather. But below that it's really hard to forecast on a day-to-day basis beyond a 36-hour period. So I look at historic patterns and even call up a local farmer or guide.”