We had a lightning strike near our previous home, and the only thing that was damaged was a hard-wired smoke alarm. The thing went off and smoke was coming from it right in the area where the switch was for turning off the noise! My DH knocked it off the wall with a hammer! We had to replace it, of course.
It's good that this topic came up now because a good time to change batteries is when we change the clocks. It's not fun, but might be a matter of life or death.