Never assume that the transportation that carries you into the winter landscape will be functioning long enough to carry you out. Always measure your emergency return path in leg miles. Easier said than done when the trail is obscured by leaves or snow. Keep an extra-careful eye out in cold weather for trail signs and blazes. Carry a map and compass and know how to use them.
Winter is the worst of times to wander from the trail.
Always bring matches or a lighter Better yet, put a full-blown commercial survival kit in your day pack just in case. But never leave home without at least a flame source for starting an emergency fire. A few paraffin- soaked firestarter sticks, such as those sold for charcoal grills, can be a big help too. In cold air, even a single soaked foot or pant leg from an accidental plunge at a small stream or creek crossing can be trouble. Don't assume that ice is thick enough to walk on.