It's very rare that it happens here, but we've had ice storms take out power for a week. The last time I remember it going out that long here was over a decade ago though (Arkansas), but Oklahoma had parts that went out close to that a couple of years ago.

The power companies here have done a lot of work burying their lines where they can. A lot of power lines can't be buried in parts the country for various geological reasons though, so outages are always a risk.