Hi: I am a EE, but I have a question that I have searched for on the Internet and not found an answer. Contractors tell me that when it has been cold for several days and the sun comes out, that buried water lines that have not frozen all winter will suddenly freeze solid. It must be a real phenomenon, because they all have the same description: "The heat drives the cold down". I would like to know if anyone has a reason that is based on the laws of physics. I have asked on another forum where there are some smart guys of various technical backgrounds, but they don't believe it. Most of them also don't believe that warm water can freeze before cold water, even after I posted to link that claims to verify it (known as the Mpemba effect". http://www.businessinsider.com/a-new-theory-explains-why-warm-water-freezes-faster-than-cold-2013-11 Any ideas?