We haven't had any power outages here (yet!) but there have been many around the country this winter. One of the necessities of modern living is being able to reach people via the telephone.
To be on the safe side, keep a corded phone around to use when the electricity goes out. The tiny trickle of electricity they use is supplied by the phone line itself, so as long as that's working, you have communication.
If you don't have a landline phone, be sure you have a charger that will work from your vehicle. Even if your phone is charged up when the power goes off, it may need another boost before the power comes back on.
Is a traditional landline phone or a cellphone better in a power outage? That depends on the storm or conditions that brought the outage.
Earthquakes, accidentally cut power lines and extreme flooding can cause landlines to fail, but high winds, hard rains and blizzards can cause cellphone signals and towers to fail.
Of course, to be safest, you can use both a landline and a cellphone and many people do that. It's an expensive option, but only you can decide whether it's worth the extra expense.