I am wondering if there is a term for the 'first snow of autumn'. The word I am looking for could come from the semantic field of meteorology, or perhaps farming etc. I know of the terms 'killing frost' and 'cold snap' but these are not really right.
The only term I've heard that relates is first frost. Farmers and folks with gardens use guides like this one from the Farmer's Almanac to plan ahead for all the bulb and perennial planting they need to do before the first frost.