The Barometer guys have just published a new episode on snow. It’s another good one. I’m starting to really miss being involved with the show!
In this episode they talk for a bit about how snow forms and it reminded me of this really nice video showing the melting layer in a precipitating cloud (click to play):
In the higher levels of the cloud (where it’s really cold) the precipitation starts out as ice and snow, which falls much slower than rain. But if you look closely at about 2 km you can see the point where the ice and snow melts and becomes rain – this is known as the melting layer. The rains falls much quicker than the snow above.
It snows at the ground when the lower levels of the atmosphere are particularly cold and so the snow doesn’t melt. This is what’s been happening recently.