When did it start snowing in Canton, Mass around John’s death?

Hi there- I’m on a deep dive watching the trial doc on HBO and it was mentioned in (I think) Ep 2 that John’s body was found with grass underneath.

My curious questions are: 1. When did it start snowing that night? 2. How much snow had fallen around 1:30A? 3. How would there be grass underneath his body if there were already inches of snow on the ground?

I’ve tried to find answers on this but haven’t found anything concrete. Thanks community!