outdoor faucet

My sister has an outdoor faucet that she has found running full force even though no one had turned it on. the first time it occured was after we had received aprrox. 2 feet of snow. The faucet is located about six inches up from a concrete patio deck, they actually had two shovel down through the 2 feet of snow to get to the faucet in order to turn it off and she said that it was on full force. It happened again after another snow storm. Could the weight of the snow somehow be heavy enough to turn the faucet on? There is no indication that anyone has been turning it on, i.e. no footprints, tracks left in the area. Any hints as to what might be the cause would be greatly appreciated.

Don't have a clue, but it isn't a bad idea to have an internal shutoff for faucets where it freezes. At least then, you don't have to dig around in the snow for it!

Take the handle off and see if it happens again. If the water pressure is excessive, that could open the valve, but I don't see how the water pressure could increase with snow?