Avalanches and winter

This tool helps prepare winter trips: it shows where the avalanche terrain is, compares it with the day’s danger bulletin and sums up the snow and weather.

Slope layer

Colors the slope of the terrain: light green 25–30°, yellow 30–35°, orange 35–40°, red 40–45° and purple 45° or more. Slab avalanches mostly release on slopes of 30° or more. It is computed from the terrain model and works everywhere; it appears from a medium zoom. You can also turn it on in the layer menu, as Slope angle.

Route analysis

Analyse the route studies the terrain every 50 m:

• Avalanche terrain (≥ 30°): stretches where the route itself crosses steep slopes.
• Exposed to slopes above: the route is flatter, but above it there are 30–55° slopes close and high enough for an avalanche to reach it.
• 25–30°: moderate slopes to watch, especially below steeper ground.

The stretches are marked on the map and on a bar along the km. Click a stretch to see it on the map.

Danger bulletin

For the chosen day (today, tomorrow or the day after), the tool loads the official bulletin of the areas the route crosses (Catalonia, Aran, Andorra, Navarre and Aragon, France, the Alps and other European services) and shows the danger level (1–5), the avalanche problems and a link to the official bulletin. Danger map of the day colors the visible areas by level.

For each stretch it works out a slope limit with a simple reduction method: danger 2 → avoid over 40°, danger 3 → over 35°, danger 4 → over 30°, danger 5 → all avalanche terrain. When the stretch matches a critical aspect and elevation of the bulletin, the limit is 5° stricter. When the bulletin gives no aspects (like ICGC’s open data), the problem applies to all avalanche terrain.

Snow and weather

At the start, the highest point and the end: new snow in the last 72 h, snowfall that day, snow depth (model), freezing level, temperatures, wind gusts and daylight.