At three in the morning during a Rockland nor'easter there is no traffic on Route 45, only the orange wash of a beacon and the sound of a blade finding pavement. Weather Defense Industries, LLC runs the storm hours in Spring Valley — plowing lots and driveways, opening walks and entryways, stacking snow where it will not cost anyone a parking space, and salting ahead of the refreeze that always follows a clearing sky. Storms here come up the Hudson valley and can turn from rain to wet snow in an hour, so the job is as much watching as pushing. The measure of a good night is that nobody thinks about it: the lot is black, the doors open, the first car in at six finds nothing to navigate. Then the sky clears, the cold slides in behind it, and the whole village goes bright and quiet.