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.
- Wispy Cirrus clouds usually signal bad weather in the near future.
- Puffy high-cumulus clouds indicate possible precipitation, but it’s often short-lived.
- The full moon is often the most stable period in the mountains.
- Strong winds or unusual warm temperatures in clear weather are signs of an incoming storm front.
- Clouds that move against the wind indicate deteriorating weather.
- Snow-forecast.com provides forecasts for ski resorts around the world, offering a solid indicator of general weather in the big ranges.
- Mountain Weather Forecasts provides weather conditions for more than 11,300 major summits worldwide. This is one of the best resources available.
- Mountain Weather covers North America’s Tetons, Mountain West, and Alaska.
- Links to commercial services can be found on Weather.gov
- Mountain Weather Forecasts is a recognized commercial resource for custom
- The Indian Himalayas bears the brunt of the summer monsoon. It is best visited in spring or fall.
- In the Nepal Himalayas, pre-monsoon (April-May) or post-monsoon (September-October) is a safe bet. Yet this range is so vast that there are many variables to consider. Off-season months are becoming more popular as climbers explore for climbing options outside the highest peaks.
- Pakistan’s Karakoram Range is drier, with the season running from June to September with July and August being the most popular months. For all of the Himalaya, a lower altitude climb (or higher climbs for extreme masochists) benefits from stable weather in winter. This is a solid, albeit cold, option.
- Peaks in the Southern Hemisphere—the Andes and Patagonia—host their seasons in reverse of North America. Their summer is our winter, and vice versa.
- The Peruvian Andes has dry weather in the summer, and winter months seeing rain. Patagonia is best in North America’s winter months.
- The Alaska Range sees most expeditions occur in May and June.
- The Canadian Rockies is a year-round destination depending on the objective. In general, climb waterfall ice in winter, high-mountain technical alpine routes in spring and fall, and big alpine rock routes in summer.
- The Tetons and Sierra Nevada are generally summer destinations, with some activity in the spring and fall shoulder seasons.
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.”
- Have the best gear on hand. “Get the best gear possible. Your life is worth it.”
- Pack so the gear is accessible. “Learn how to pack priority items like goggles and hard shell pants where you can get them out fast.”
- Learn to put it on and take it off. “You’ll need to be practiced in deploying your severe weather clothing quickly to stay warm and dry.”
- Practice your systems at home. “Test the same gear you’ll be using in the mountains. It’s extra work but well worth the effort.”
- Have a plan and itinerary.
- Be prepared to adjust the plan.”
- Nurse your psych and don’t spend time fretting over things you can’t change.
- Be patient.
- Be ready to go if the weather is good.