Looking at the counts from the beta/gamma detector, it looks a lot like normal background radiation.
Sporadic hits, and I can't see what the sensitivity of the GM tube is set at. 42-46 CPM is considered normal background activity.
I don't even get interested until it pops above 100 CPM on the ground, and flying in a commercial airliner at FL 35.0 gets you closer to 900 CPM.
If I set my own Victoreen 491 to 0.1x sensitivity with fast needle response, it'll jump around all day long to radon, cosmic rays, cinder block, etc.
Put a piece of orange pre-war Fiestaware in front of it, and it'll light up like a christmas tree.
Questions I'd ask, were I still tasked to check it out, would be calibration date of instruments, age of GM tube, instrument settings, readings in different areas, and samples gathered for counting.
IOW is it the snow? Is it the ground under the snow? Is the detector set to high gain and spiking on cosmic rays? What does it read across town? What does it read on the other side of the county?
I know what it reads all over the US.
http://epa.gov/radnet/