My comment was a bit short and blunt. No disrespect intended to the teaching profession. I have a brother, a niece, and a sister-in-law who teach. Schools here close several times each winter due to road conditions that I certainly wouldn't want to drive a bus on. Snow days for him usually put him working in his son's sugar woods.Uh...I think its about getting kids to school safely....and nothing to do with teachers.
That said, some states/districts have a different interpretation of safety.
Fyi...my teacher wife has never had a snow day. 35 below is the magical number. Snow/drifting has never been a factor.