The slopes under Prospect Hill Park become a different town when it snows — pitched driveways, tight turnarounds, an icy last twenty feet that decides everything. Medina Tree Services works those in winter: plowing and clearing driveways and lots, shoveling steps and walkways, salting the grades where a car would otherwise slide. Snow on that side of Waltham is often an inch deeper and an hour longer than downtown. Getting a hill driveway open before the morning rush sets the tone for the whole day. Serving Waltham along with Weston, Lexington and Belmont.