Thunderstorms are something to plan for before a hike, not simply endure when they break. In the mountains, the terrain, ridges, summits and open spaces increase your exposure. The best decision is often made several hours before the first flash of lightning.
Putting thunderstorm risk into perspective
A forecast of thunderstorms does not mean every outing is out of the question. It does mean thinking carefully about timing, terrain and alternatives. Check mountain weather forecasts the day before and again in the morning, paying particular attention to how conditions will develop throughout the day. If storm cells are forecast early or thunderstorms look widespread, choose a lower-altitude, shorter outing or postpone it.
On the trail, keep an eye on both the sky and the time. Oppressive heat, rapidly growing cumulus clouds, shifting winds or distant rumbles all provide useful clues. Waiting for the first rain before making a decision rarely leaves enough time to act.
Planning your route to leave exposed areas
Identify ridges, passes, summits, arêtes, lakes, open areas and sections equipped with fixed aids in advance. Ask yourself where you will be when the risk increases, and whether you have a straightforward, quick-descent option. A route with an easy escape option is often better than a spectacular loop with no way to retreat.
Set a firm turn-around time or a deadline for leaving high ground. This must reflect the group's actual pace, not just the time estimated by an app. If the group is running late, adjust the objective; do not try to make up time by moving faster across more exposed terrain.
If a thunderstorm is approaching
Leave high ground and open areas as early as possible. Keep clear of summits, ridges, isolated trees, cables, watercourses and rain-soaked rock faces. Do not seek shelter under an isolated tree. Spread the group out so that a single incident does not affect everyone, and avoid holding metal objects.
A car or an enclosed building offers better shelter if you can reach it without taking additional risks. A mountain hut can provide protection from the weather, but it must not become an unreachable goal once conditions have already deteriorated.
After the storm: do not carry on as though nothing has changed
Rain can make rock slabs, roots, scree and stream crossings much trickier. Visibility may remain poor, while cold or stress can increase fatigue. Take time to reassess the group, the remaining route and the time of day. Shortening the outing may still be the right choice.
Preparing a plan B, setting off early and being willing to turn back are not restrictions. They are habits that allow us to keep enjoying the mountains for years to come, with care, independence and pleasure.
Frequently asked questions
Is waiting out a thunderstorm under a tree risk-free?
No. An isolated tree, a ridge, an open area or a watercourse is not suitable shelter. Planning ahead means leaving exposed areas early and heading for an enclosed building or a vehicle only if you can reach it without putting yourself in greater danger.
What if the group is already running late?
Do not try to make up time by moving faster through an exposed area. Choose a lower-altitude, shorter alternative or turn back: a shrinking safety margin is precisely when the objective needs to change.