Due to the climate crisis, extreme weather is becoming increasingly common – this also applies to severe thunderstorms, which pose multiple dangers for mountain hikers. In this article, you'll learn how to behave properly during thunderstorms in the mountains.
Severe thunderstorms are among the greatest risks for mountain hikers in the Alpine region during the summer season. Recently, three hikers from Austria were killed by a lightning strike in the Stubai Alps. The group had set out that morning for a hike up the 2.635-meter-high Mittagspitze and were surprised by a sudden change in the weather.
To better prepare mountaineers Storm To prepare and minimize risks, the Alpine Club Austria important tips summarized.
Watch the weather, start early
In addition to the dangers of cold and damp, which cause hypothermia and an increased risk of falls, there is also the immediate danger of lightning strikes during thunderstorms. To minimize these risks in advance, the Austrian Alpine Club to conscientious tour planning (for example with services such as Alpine Club weather) and careful cloud observation on the day of the tour.
According to expert Jörg Randl, head of the mountaineering department at the Alpine Club, weather forecasts always only indicate probabilities – thunderstorms could occur earlier than predicted. Therefore, it is advisable to closely monitor the weather developments of the past few days and the current conditions during the tour.
If cumulus clouds develop earlier each day and cumulus clouds are already visible in the morning, thunderstorms can be expected in the early afternoon.
Jörg Randl, Head of Mountain Sports Department ÖA
Especially in the summer season, an early start brings clear advantages, says Randl: "If there are corresponding warnings, the planned route should be adjusted so that, ideally, you have already started your return journey by midday or, at best, have already found shelter in a mountain hut."
Immediate warning signals
Warning signs of an approaching thunderstorm include towering, anvil-shaped storm clouds, gusty winds, and an audible hum in the atmosphere.
The approximate distance to a thunderstorm in kilometers is calculated by dividing the seconds between lightning and thunder by 3: If there is a time span of ten seconds between lightning and thunder, the center of the thunderstorm is only about three kilometers away.
When the storm comes
If you are caught in a thunderstorm on the mountain despite planning, you can protect yourself with these tips:
- Exposed ridges and isolated elevations such as summit crosses and rock towers leave as soon as possible
- If possible, larger rock caves seek shelter, distance from the rock face at least 1,5 m
- In crouching position squatting on a backpack or rope and waiting with your legs closed on this insulating surface for the storm to pass.
- On via ferratas and in terrain where there is a risk of falling remain secured on the steep rope using a via ferrata set: The risk of falling is greater than the risk of lightning strikes!
- Gegen Wetness and cooling Protect yourself with a bivouac bag and functional clothing
If there is a risk of thunderstorms, we opt for a tour with an early return or with the option to abort (Graphic: Georg Sojer/Alpenverein) 
In rock niches we keep enough distance from the rock. (Graphic: Georg Sojer / Alpenverein) Crouching position with closed legs on an insulating surface. Keep your distance from watercourses and free-standing elevations such as masts or trees. (Graphic: Georg Sojer / Alpenverein) On rock faces, we are safe from lightning strikes, but it is important to be aware of the risk of falling rocks. (Graphic: Georg Sojer / Alpenverein)
Thunderstorms are often accompanied by heavy rainfall. Within a short period of time, dangerous flash floods can occur in rock faces and cause rockfalls. Randl therefore warns: "The main danger during heavy rain is complete soaking and the associated hypothermia."
On alpine climbing routes and via ferratas, quick evasive maneuvers are impossible, making the situation even more difficult. If you find a sheltered spot, it's usually better to wait out the storm there rather than hastily climbing toward the exit and then being exposed.
On days with very unstable weather, avoid: extended tours or routes with wire rope safety on exposed ridges and freestanding peaks.
Jörg Randl, Head of Mountain Sports Department ÖA
Video: Rules of conduct during thunderstorms on the mountain
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Credits cover photo: Alpine Club Austria/Melcher