I have to disagree with everyone else here.
You definitely did right to notify her. But I say, if you're willing to pay to have her electricity turned back on, I would. Just let her know you took care of it and she can pay you back whenever she's able to. I'd pay the minimum amount you can get by with paying, not the total amount she owes.
Either way, she's going to be embarrassed that you know her power went out. At least this way, she won't have to cope with not having heat or light, with spoiled food, etc.
As for her not answering, she may have her phone off for the funeral, or perhaps her cell phone account got turned off, too. What I mean is, she may not have received your text or may be unable to answer.