Snow reaches Norwalk off the water — wet, heavy, and usually falling hardest at four in the morning when nobody is awake to see it start. New England Paving Company LLC works that hour, clearing snow ahead of the day so the ground is passable when the first car finally needs it. It is unglamorous labor, done in headlights and breath-steam, and it is measured by exactly one thing: whether the way out is open. Winter on this stretch of the Connecticut shore gives little notice, so the answer is to already be moving when it arrives. The company covers Norwalk and the Fairfield County towns around it.