Climate and Weather
One of the most important things to consider while planning an expedition or trek in the mountains is the prevailing climate during your expected period of travel and the possible weather conditions you might encounter. While extreme cold and snow are almost unavoidable on expeditions and high altitude treks, a general rule of thumb in mountaineering is that the best time to plan a climb is in spring, early autumn or summer. The weather during these seasons is more or less suitable with relatively less winds and snow. However, this might vary from one mountain range to another and the best season for climbing depends on the location. Regardless of the location, you can expect rougher weather conditions during the winter and early spring months with heavy snowfall, strong winds and highly unpredictable weather. It is crucial to understand the weather of the location and be fully prepared to tackle any changes in the climatic conditions without too much difficulty. The following are a few points that will help you understand and read mountain seasons and weather better:
1. Mountains are known to be notoriously unpredictable in terms of weather and climate. Sometimes even the most ideal weather forecast could prove to be inaccurate. You might start off your journey on a bright sunny day only to have the clouds build up and get caught in a storm that there was no forecast for! The increase in altitude is directly proportional to the rise in winds and precipitation. For every 1000m you gain, you will notice a temperature drop of approximately 6℃. Simply speaking, weather conditions in the mountains get windier, wetter and colder when compared to low altitude regions.
2. Use an effective weather forecast app and keep an eye on the conditions while planning and also in the weeks leading up to the climb. Check the weather for the exact location of your climb and not the nearest town or base camp. Do not limit your checks to temperature alone. Make a note of wind speed and the possibility of precipitation. Do not hesitate to postpone your trip if the weather forecast has changed for the worse.
3. Get in touch with the locals. Nobody understands mountain weather better than the locals who live in the region. They will be able to tell you if your planned dates of travel are ideal, how the weather might change, direction of winds and rain and actual temperatures. Speak to them and get a thorough idea along with tips on how best to navigate the route in different weather conditions.
4. Keep an eye on the sky. This could be your best tool for weather forecast while actually out on the expedition or trek. You will learn to read mountain weather better with more experience but a simple point to remember is that if you see the weather changing quickly, adjust your plan to avoid getting stuck in bad conditions.
5. Understanding the clouds above you. Once you have figured out how to read the clouds, you will be able to predict if a storm is headed your way and how severe it is going to be. Lenticular clouds, which typically have a distinctive shape like that of a flying saucer, are bound to bring a storm in the following 6-24 hours when accompanied by strong winds. Cirrus clouds are found in higher altitudes and have a detached and hair-like look. If you spot them alone, the weather is going to be alright. However, if you see them in a combination with low stratus clouds (low level clouds with a uniform base, usually white or grey in colour), you can expect precipitation. Cumulus clouds are fluffy, cotton-like clouds with a flat base and usually indicate good weather. However, if you notice them getting bigger with more bumps, it could mean they are turning into cumulonimbus clouds that bring lightning, thunder, strong winds and even hail.
6. While not always true, if you encounter moderately bad weather at lower altitudes, it is likely that the weather conditions are worse higher up.
If you are carrying a pocket barometer, you can keep a check on the air pressure. A sudden drop in air pressure means that a storm is approaching.