Updated: Sep 23, 2019
The first thing that you need to know about weather is that it can change unexpectedly, epecially when you are close to or in the mountains.
In the mountains it can snow in August and you can see sunny mountain tops in the distance while you are getting soaking wet in a small thunder storm.
Unpredictable weather forms a huge risk when you are walking through the wilderness. Always be prepared and travel with the appropriate gear for the location.
Planning your trip
When you plan your trip, you should always check the weather history of your destination. It's easy to find historic weather patterns online for almost every destination and it will provide you with an average temperature, rain and wind speed info.
When you are walking through the mountains in the summertime, you can often get caught by a late-afternoon thunderstorm. This means that you need to get to a safe place like a hostel or gîte before the rain kicks in. If this is a repetitive weather situation, you should start walking early in the day in order to cover a larger hiking distance.
Be aware if you set up camp in the wild. Stormy weather can be very damaging for your tent, gear and, most importantly, your life. Think about lightning strikes, heavy wind gusts and possible falling trees, heavy rain that causes falling rocks and flash floods in dry looking river bedding.
Always keep your fingers crossed for the weather on your trip, but pack your bag with a worst case scenario in mind. Carry reliable weather gear and make sure that your spare clothes are packed in a waterproof compression bag.
Have a close eye on the weather during the trip. Even deep in the woods, smart phones might work, so if possible, check the weather in the evening to be prepared for the next day. You can also ask locals if you pass by some small villages or talk to other hikers. Some people who go to very remote places carry a small AM radio for this purpose.
The sky is the limit
Watch where you walk, but also take the time to scan the sky for emerging cloud formations. The shapes and movements of clouds can tell a lot about the arrival of warm and cold fronts.
Warm fronts are formed when the warm air pushes away the cooler air. Warm fronts travel at half the speed of cold air fronts. They rarely produce heavy weather. Warm fronts progress from thin, high-level cirrus clouds to low, dense stratus clouds.
Cirrus clouds are thin clouds and look like white brush strokes on blue canvas, high in the sky.
Cirrocumulus clouds appear as small puffs and have rippled rows. They are followed by cirrostratus clouds that take in large areas of the blue sky. They are filled with ice crystals and float really high.
Altostratus are dense mid-level clouds and they are typically followed by nimbostratus clouds that look like gray, thick, low-level clouds. These last ones usually carry the precipitation. This can turn from small drops into steady rain or in low temperatures, even snow. Low hanging stratus clouds look monochromatic and carry moisture.
Cold fronts are cold air masses that find their way around and under warm air areas. They can develop quite fastly and move swiftly. They cause sudden wind directions followed by a temperature drop. This can be noticed by a decline in the barometric pressure.
Cumulus clouds are puffy and white of color. First they are diffused but they tend to travel upwards and travel closer to each other. Rain may come late in the day.
Cumulonimbus travel vertically through the sky and expand from their original puffy white state to huge cloud fields. They reach up high unto the upper atmosphere. Sometimes they are shaped like an anvil. These classic clouds predict severe weather. Cumulonimbus clouds also form independently of cold fronts, and are mainly seen in the late afternoon or on very warm days. They often produce late-afternoon thunderstorms.
Lightning is present in all thunderstorms. Lightning bolts cause the air around them to expand and contract in a short period of time. This incredible energy force produces thunder.
Every year, multiple people are injured or die because of a lightning strike. Never walk casually through an electrical storm
Have a close look on the different situations and tips bellow:
Move as for away as possible from tall trees, especially if they are standing solitarily in an open field. High rising objects are more likely to attract lightning.
If you are on a ridge or peak, it's better to descend to a lower laying area. Always head for lower ground, but stay away from open areas.
Stay away from water! Don't cross any rivers, lakes and small streams during a thunderstorm.
If you find a hide out like a cave or cliff, get as far away from the opening as possible. It's nice to stand almost outside and watch the storm, but the current from the lightning can jump across gaps and could jolt a person standing in the opening of a cave.
Insulate yourself from the ground. Sit on your backpack or sleeping pad. Do not lie down, but crouch on the ground with your feet close together.
If you travel in a team, you should spread out and sit at least 10m away from each other if possible.
When a person is hit, they can be revived by CPR. Be careful, however, for a second strike on that same area and watch out for an electric shock as the current doesn't leave the body of a victim immediately.
The best place to be when you are hiking in the wild is within a group of trees in a lower area. Or if you haven't got another option, go to a low spot in an open meadow.
Do you want to know how close a lightning bolt is to your location? Look at your watch and count the seconds between the lightning and the thunder. If it's 10 seconds apart, the center of the storm is 3,5km away; 5 seconds means 1,3km and 1 second... well, you are in the middle of it now... Good luck!