Growing up in Northern Ontario, one learns these lessons early. Anything on, or more importantly, embedded in, the ground was always subject to frost. Roads seemed to take a few yearly cycles to get moved enough to matter, but anything with fence posts or pilings caused a lot of damage. The conversations among the local cognoscenti: "didn't go deep enough", "never use concrete!" , "needed more concrete", etc. No one really had the answer...always seemed a crap shoot to me. This lack of knowledge left every neighborhood looking like it just went through a minor earthquake each spring. Apparently, helical piles are the next great thing to try... I wonder how deep I need to go....