Why does freezing rain more commonly occur with warm fronts than cold fronts?
The warm front advances over the cold air so you have a tempurature inversion. The air just above the ground (like 300 feet) and above is actually warmer than the air at the surface. Rain falls through the warm sector and then freezes in the cold area close to the ground. If the cold sector is higher then you get sleet. Snow needs cold tempuratures throughout the distance from the ground to the cloud.
