Contents
The map shows new snow of the last 72 hours and a snowfall forecast you can slide from one to seven days ahead, live snow depth from measuring stations with a 7-day chart, webcams, and a weather forecast for any point: seven days, with hourly sun, precipitation, snow or rain, wind and gusts at about 3,000 m, freezing level and snowfall line.
New snow and the snowfall forecast
The new snow layer colours the terrain by how much snow fell in the last 72 hours. The snowfall forecast layer does the same for the days ahead, with a slider from one to seven days. Both sit on the 3D terrain, so you can see which valleys and which sides of a range got the snow.
New snow is the first avalanche problem to check: the bulletin names it when fresh snow has not bonded to the old surface. The layer shows where that snow is; the bulletin says what it means. Read them together, and read how to read an avalanche bulletin if the problems are new to you.
Snow stations
The snow stations layer shows measuring stations with their live snow depth and a chart of the last seven days. French stations link to their page at Météo-France. A station tells you how much snow there is at that spot and whether it is growing, settling or melting; it does not tell you what the snow is like on the slope you want to ride.
Webcams
Hover a webcam for its live picture and click to open the camera on its own page. A webcam answers questions a forecast cannot: is it snowing right now, how high is the cloud base, is the face already tracked out.
Weather for a point
Search a place, pick a point or use the map centre, and the weather tool gives the conditions now and the new snow of the last three days, a 7-day forecast, and under "More info" the hourly detail: sun, precipitation and its probability, snow versus rain, wind and gusts, also at about 3,000 m, the freezing level and the snowfall line. It also lists the nearest snow stations and the avalanche danger for that spot.
The freezing level and the snowfall line are the two numbers to watch for wet-snow days in spring and for rain-on-snow days in winter. Wind and gusts at 3,000 m tell you from which side the snow has been moved; the bulletin says what that did to the lee sides.
Where the data comes from
The forecast comes from a numerical weather model; the stations and webcams from their operators. We name them here once we have their consent.
What it doesn't show
- The forecast is a model. Mountain weather turns faster than any model; check again in the morning.
- A snow station measures one spot, usually a flat site. The depth on a slope, in a lee or on a ridge is different.
- The new snow layer shows how much fell, not how it bonded. Wind transport and slab formation are not on the map.
- Webcams depend on their operators and can be offline, frozen over or pointed elsewhere.