Christmas was coming. One morning in mid-December, Hogwarts woke to find itself covered in several feet of snow. The lake froze solid and the Weasley twins were punished for bewitching several snowballs so that they followed Quirrell around, bouncing off the back of his turban. The few owls that managed to battle their way through the stormy sky to deliver mail had to be nursed back to health by Hagrid before they could fly off again.