Wet soil and 30 below for a couple weeks will freeze to 6 feet.
Its pretty dry up here normally, so we are usually safe at 6 feet, 7 feet under a road.....but I have seen it freeze to that depth a few times.
The freeze up Saturday was not nearly that deep. Maybe only a foot once the water stopped flowing.
Yeah, frost line in Anchorage is ~ 12 feet, but I've seen it freeze 15 feet down and rupture water mains and sewer mains.
Here, in NE Texas, I think the frost line is ~ 2 inches.
Ed
