What the snow layer means
Check whether the legend describes snow depth and whether it uses centimetres, metres or another unit. A depth value refers to the existing snowpack at the selected time, including the modelled effects of earlier snowfall and subsequent change.
Do not treat that number as fresh snowfall during the next hour. A snowy mountain can remain coloured through a dry day; a snow shower may also fall where little snow settles.
Compare snow, rain and temperature
Move through the forecast and compare the same time on the precipitation and temperature maps. Near the rain–snow boundary, relatively small changes can alter what falls and what stays on the ground. Air temperature alone does not describe the whole layer of air through which precipitation travels.
Snow depth and the water contained in snow are different quantities. A millimetre of precipitation does not always produce the same depth of fresh snow, because snow density varies.
Use local winter information
Terrain, drifting, compaction and melting create differences over short distances. Compare relevant elevations in the Rockies, the Scottish Highlands, the Australian Alps or New Zealand’s Southern Alps. Winter falls in different months between hemispheres. Add local snow reports, road information and avalanche guidance where relevant; the map cannot confirm a safe route.
Questions about this map
Is this a live snow radar?
No. The initial layer is a snow-cover forecast. Use the rain radar for available precipitation imagery and check whether the provider identifies snow.
Does 20 cm mean 20 cm of new snow?
No. A snow-depth layer estimates the total snowpack at the chosen time. Fresh snowfall and accumulated ground snow need separate interpretation.