Plan your second crossing before the storm

Most commuters know their route by heart and their detour not at all. A bridge or tunnel that closes for ice, wind or a stalled truck turns a 25-minute drive into a guessing game, and phone maps are slowest to catch up in the first hour of a closure.

1. Count your crossings

Write down every bridge, tunnel and long overpass between home and work. Include the small ones over rail lines and creeks: they freeze first, because cold air runs under them as well as over.

2. Pick one alternative for each

For every crossing, find the next way across. On a river city that might be the bridge one exit up; for a tunnel it might be a ring road. Avoid steep approaches and streets that are plowed last.

3. Drive it once on a clear day

This is the part that matters. A detour you've driven is one you can follow in blowing snow. Note the turns that surprise you, and how long it takes compared with your usual route.

4. Put it on paper

Mark both routes in a paper road atlas and leave it in the glovebox. Phones run flat and signal drops; paper does neither. If you navigate by phone, a dashboard phone mount keeps the map at eye level instead of in your lap.

5. Set your turn-back rule

Decide now: if your crossing is closed and the detour adds more than, say, 40 minutes, you work from home or wait it out. A rule made on a calm evening beats a decision made at a red light.