I was watching the first episode of The Universe series on Blu-Ray yesterday, and they talked a bit about solar storms and their potential risks (overloading powerlines, possible dangerous levels of radiation exposure for airplanes in flight near the poles, etc.).

A bit more reading on the subject suggests that solar storms are a serious risk to astronauts in orbit around the Earth or on the Moon.

I'm wondering, though, at what distance from the Sun do solar storms cease being dangerous to astronauts?

If astronauts were orbiting one of the outer planets, would a solar storm still present a serious risk of radiation exposure?