Meanwhile, in the NE, it has to snow 12' to cancel school.
by NE you mean northeast? I grew up in Boston and had school canceled on as little as four inches, and not canceled on as much as 10" - but yes, 12 is just about a guarantee.
It's all about how ready the plows are - which means when the snow starts falling. If it starts in the evening, then by morning the plows will have taken care of all of it and school's ready to go. However, if it starts at 3am or later, then a few inches dumped on the ground at 6am is enough to disrupt school bus service completely.
another factor to note is what season it is, which determines how surprising the snowstorm is. In January, the plow crews are ready to go and intently watching the weather channel. May, not so much. Six inches, starting at midnight on May 18, was a perfect birthday present!
speaking of snow crews, the best I've ever seen in the business was (not surprisingly) Anchorage. 16" fell overnight, starting around 7pm, and the roads were functional by 6am and just about completely cleared by 11.