Chris, Mike, Richard -
The permafrost line is north of my area and moving pole-ward every year; I don't think that will be an issue. I will have to look into the nature of liquefying soils, though, as I can't say whether or not that's what is in my valley from looking at it.
Thank you guys very much. I'm going to return to this thread when I've digested your comments , and I appreciate the time you gave to sharing your knowledge.