DO A BACK-UP BEFORE YOU DO THIS. Of course, they had me do it all on my own, because they couldn't tell me that I had to do it, but, it worked. My watch was blowing through 8-12% of my battery life every hour, but since I did this, 3 hours ago, I've lost 6% of my battery. This is also after installing a bunch of apps, and re-enabling background app refresh and notifications too!!
You can defrost ground beef in any number of ways; a bag of flat frozen ground beef will thaw in the refrigerator in under two hours or in the microwave in less than five minutes. But my favorite way to defrost is to transfer the bag from the freezer to a large bowl in the sink.
I give you a GA for wait till spring. That is the only answer if there is 4 feet of frost. You will not thaw the ground with a bonfire and you may need more energy to attempt a thaw than it is worth waiting a couple or three months. Piling material on the area will insulate the ice and delay the thaw.