Weather and Mountain Safety in the Alps
Mountain weather in the Alps kills a consistent number of people each year, and most of those deaths involve decisions that were avoidable with better forecast awareness or more disciplined route timing. This is not a subject that benefits from vague generality: the mechanisms are specific, the forecasting tools are excellent, and the protocols are clear. Apply them.
The forecasting tools
MeteoSwiss (meteoswiss.ch or the MeteoSwiss app) provides the standard mountain weather forecast for Switzerland, with a dedicated Mountain Weather section covering individual massifs and passes. The 3-day forecast is reliable; the 5-day gives useful pattern information but not precision. The mountain forecast includes summit wind speeds, freezing level, precipitation probability, and convective risk rating — all the variables that matter for route decisions.
Météo-France (prevision-meteo.fr or the Météo-France mountain section) provides the equivalent service for the French Alps and Pyrenees. The Météo-Montagne bulletins — issued each morning for named massifs including Mont Blanc, Belledonne, Écrins, and Vanoise — are the standard reference used by French guides and refuge guardians.
Alpenverein-Wetter (the DAV/ÖAV forecast at alpenverein.de) covers the eastern Alps and Bavarian range. The Lawinenwarndienst (avalanche warning service) sections for each Austrian state and Switzerland provide the same data for winter and spring.
For a one-line heuristic: check the forecast the evening before for the next day's route, and again at 06:00 on the day of departure. If either forecast shows afternoon thunderstorm probability above 50% or a significant cold front approaching, revise the plan before leaving the hut.
The afternoon convection pattern
The Alps in summer generate a predictable and reliable pattern of afternoon thunderstorms. Solar heating of mountain surfaces creates thermal uplift from mid-morning. Cumulus clouds develop above summits by 11:00–12:00 on most summer days. By 13:00–15:00 these develop into cumulonimbus — thunderstorm cells — that produce lightning, hail, and intense short rainfall. By 17:00–19:00 the storms typically dissipate.
This pattern is not a rare event requiring special forecast warnings; it is the normal summer afternoon in the Alps. The forecast distinguishes between light isolated convection (low risk) and organized thunderstorm lines or cold fronts (high risk), but even light convection can produce a dangerous lightning event at summit level.
The operational response is simple and universally observed by experienced alpine travellers: plan routes to be below exposed ridges and off summits by 13:00–14:00 on days with convective potential. Plan routes to be in the hut by 14:00 on days with high thunderstorm probability.
Lightning protocols
Lightning in the mountains is a direct and immediate risk. Fixed metal infrastructure — via ferrata cables, summit cross ironwork, cable car pylons — greatly increases this risk because it provides a low-resistance path to ground across a large area.
If lightning is occurring and you cannot reach shelter:
Avoid ridges, summits, and high exposed ground. Move to the lowest available terrain, not the highest.
Stay away from all metal objects. Disconnect from via ferrata cables. Move away from cable car pylons, survey cairns with metal poles, and fence lines. Stay away from cave entrances — the ground current from a nearby strike travels along rock surfaces, and cave entrances channel this current.
Crouch — do not lie flat, do not stand upright. Feet together. Crouch on an insulating pad (your pack) or at minimum on your boot soles. This minimizes the surface area between your feet and reduces step voltage risk.
The 10-second rule: if the interval between a lightning flash and thunder is 10 seconds or less, the lightning is within 3 km. If it is 5 seconds or less, it is within 1.5 km. At this distance, the probability of a strike in your immediate area within the next few minutes is significant.
Whiteout protocols
Whiteout conditions — where cloud, fog, or blowing snow eliminate all visual contrast between snow surface and sky — occur at altitude on any day with cloud. In a whiteout, glaciers and snowfields become featureless, crevasses become invisible, and ridge lines disappear. Navigation by terrain feature becomes impossible.
The correct response to a developing whiteout on a glacier or snowfield:
Stop before you lose all visibility, while you still have a reference point. Take a GPS bearing to your destination and note the compass heading. Move slowly on that heading, probing with a pole or ice axe ahead of each step to detect crevasse lips. Do not continue on gut instinct — the spatial disorientation in a true whiteout is extreme and reliable.
On mixed terrain with rocks and ice, whiteout conditions make steep descents extremely dangerous — depth perception disappears. Stop, anchor, and wait for visibility to improve if safe to do so.
Glacier melt windows
Glacier snow is most stable — and crevasse bridging most reliable — in the cold morning hours before solar heating. From approximately 10:00–11:00 on a clear day, surface melt begins. Bridge strength decreases. Roped travel is always required; fall-in-crevasse probability increases as the day warms.
The standard alpine guide practice is to cross glaciers before 10:00. A 05:00 departure from a high hut allows 4–5 hours of glacier travel in good conditions. This is not tradition for its own sake; it is a response to the physics of snow structure.
Communicating plans
Before any serious alpine route, file your plan with: the hut guardian (who provides your emergency contact in the area), a responsible contact at home (who knows your route, expected return time, and the relevant mountain rescue number), and where possible in a paper entry in the valley route register if one exists.
Mountain rescue numbers: Switzerland 144 (REGA), Austria 140 (Alpine rescue Bergrettung), France 112 or 15 (SAMU), Italy 118, Slovenia 112, Germany 112. Most mountain rescue apps (REGA app, ALP ICE for the Alps) also allow GPS emergency alert.
The hut as a weather refuge
The hut guardian in a staffed alpine hut is your best local weather resource. They have been watching the sky above their location for years, they have received the morning MeteoSwiss or Météo-France bulletin, and they know the local microclimatic patterns that no forecast captures. Ask at dinner what the next day's weather looks like. Ask at breakfast if the forecast has changed. If a guardian recommends a shorter day or a valley descent, take the advice seriously. It is offered from experience, not caution for its own sake.
Emergency communication and satellite devices
In the event of an incident on a serious alpine route, standard mobile phone coverage cannot be relied upon above the treeline. Where coverage exists in valleys and on popular routes, it is intermittent and altitude-dependent. The practical solution is a satellite communicator: devices like the Garmin inReach Mini 2, Zoleo, or SPOT allow two-way messaging and SOS activation anywhere on the planet via satellite. The monthly subscription costs approximately €15–25 and provides rescue coordination capability that transforms the risk profile of any remote route.
A personal locator beacon (PLB) without a subscription — such as the Ocean Signal PLB — provides one-way SOS activation via the COSPAS-SARSAT satellite system, free of charge beyond the device cost. PLBs are one-use emergency devices rather than everyday communicators; they require registration with the national authority before use (COSPAS registration is free).
For popular summer routes on the SAC and DAV hut networks, mobile phone coverage is often adequate during the staffed season. For winter touring, less frequented routes, or any route outside western Europe's well-covered terrain, satellite communication is the appropriate standard.
Foehn and its effects
The foehn wind is the specific meteorological phenomenon that dominates alpine weather patterns in spring and late summer. It is a warm, dry downslope wind that develops when a pressure gradient forces air over the Alps from the south; the air warms and dries as it descends the north side. Foehn events produce exceptional visibility, dramatic lenticular clouds on the ridges, and a warmth that can be 15–20 degrees above the ambient temperature for the time of year.
Foehn is seductive — the crystal clarity and warmth feel like perfect mountain conditions. In practice, a foehn wind is also a warning of an approaching frontal system on the south side and a trigger for rapid snowpack destabilization in winter and spring. The foehn typically lasts 24–48 hours before the front that drove it arrives from the southwest. Experienced alpinists treat foehn conditions as a closing window rather than an extended opportunity.
See them all in one view
Mountain huts providing weather information and refuge — including high SAC and CAI huts with guardian weather briefings — are plotted on the Open the map.