In my dialect, which is some sort of American English, trying to snow someone means trying to BS or con them.

Blindsiding someone means taking them unawares - hitting them when they aren't looking, physically or metaphorically.

A speedball has cocaine in it, which is sometimes known as snow.

"Iced" can mean killed, but the Urban Dictionary definition is oddly specific

I agree about "snowballing" meaning increasing in size or momentum, but it doesn't have to refer to a problem.