A couple of years ago, my son bashed a riser, so we took it out. It was buried about five feet deep. We decided we didn't really need a riser right there, so we removed the damaged riser, capped the line and filled in the hole. Last summer, a riser near the house was leaking in several ways, so we decided to replace it. We went to the store and there were eight foot long risers. We figured five feet deep plus three feet above ground would be about right. When we dug up the leaking riser we were a big surprised. It was only three feet deep. Oh well. So we ended up with a five foot high riser. A little weird, but oh well. Yesterday it got to 27 degrees below zero (F) and the riser worked fine. Today is 5 degrees above and the riser will no longer work. My theory is that all that extra metal conducted the cold the full three feet down and now there is a big gob of ice down where there is supposed to never be ice. Could this be the case?