How can a layer of snow stop young plants dying in the frost?

This is a physics question of mine.





Couple of thoughts of mine:





-Supplies plant with water from melting snow?





-Snow insulates the plant somehow with air pockets?How can a layer of snow stop young plants dying in the frost?
It insulates the plants. snow is 32 degrees, the freezing point and doesn't get much colder than that. the outside temperature can get


-20 or colder, cold enough to kill young plants.