A nor'easter announces itself on Chalkstone Avenue before it does anywhere else — the wind swings around, the light goes green-gray, and Mount Pleasant's uphill streets start disappearing from the top down. Handrigan Renovations LLC gets out ahead of it, clearing driveways with the plow, shoveling walks and entryways, salting the grades where a car would otherwise slide back into the street. Uphill drives take a different approach: clear early, clear again, and never let the base pack. Getting somebody out of their own driveway on a Tuesday morning is the entire measure of the storm. Then it's the next street, and the one after that.