Tropical Storm Isaias is headed for the northern Gulf Coast, and forecasters expect it to come ashore as a hurricane late this week. Gulf Coast families know the drill. Board the windows. Gas up the truck. Stock the pantry. Then wait to find out how long the power will be out.

Sometimes it’s hours. After a big storm, it can be days. The line crews work around the clock, and they still can’t reach every street at once.