Thanks, Brad Johnson, for that graph on solar activity in that period. I guess the thing to do is check for similar spikes in other cities over that time period, but I'm too lazy to do that. (By the way, shouldn't the OP's "59 counts per minute" have been "59 counts per second?")
I reckon that while normal variations in background radiation are not much to get wet-your-pants panicy about, there are instances where ignorance (or coverups) have led to deaths, with both radioactive substances and other things.
The radium watch-dial painters and Madame Curie come to mind. I don't know about the other radiation pioneers... like for instance, did Becquerel have any problems after he x-rayed his hand?
Asbestos also comes to mind, and possibly PCBs (Polychlorinated biphenyl),
Then there's the unprovable but highly suspicious deaths of so many of the participants involved in filming the movie "The Conqueror" with John Wayne and Susan Hayward:
http://en.wikipedia.org/wiki/The_Conqueror_(film)#Cancer_controversySo I'm not going to wet my own pants about somebody finding "radioactive snow," but on the other hand, it's something to tag for "keeping an eye on."
Terry, 230RN