I live in North Eastern British Columbia. We get a pretty solid layer of snow from October thru May. I have done numerous flights in my region this winter and do not encounter ANY snow on the ground until I am well into the mountains. At first I thought maybe the snow cover was limited to a specific altitude. We are only at 2300 ft ASL here so maybe as the ground elevation goes up the snow cover is greater. I recently did some tooling around Vancouver (CYVR) I noticed that the entire Fraser Valley area had significant snow cover. More than I encountered at some of the higher altitude areas while enroute from the north. So the altitude ‘zone’ for snow cover theory was crushed. The Vancouver area is mostly less than 100ft ASL !
For those unfamiliar with the area what we refer to here as ‘the Lower Mainland’ gets very little snow year round. It is a coastal rainforest region with a very temperate climate. I cannot make any sense of the ground cover algorithm being used.