I don't know, just a hunch, but I know that during winter there was strong El Nino pattern going on. It brought a ton of heavy winter storms through the middle of the United States. Probably the most memorable one to Americans in general is the one that brought like 3 feet of snow to areas like Washington D.C. and Baltimore.
One of the storms before that brought the first blizzard warning in my county, on Christmas Eve. Was quite epic for me. I love snow. ^_^
Now I don't know if the pattern is still around, but I know that it is known for pushing tons of strong systems through, and this may still be part of that line of storms pushing through. I don't know, I'm not a meteorologist or anything. But the world isn't ending. There's always something strange going on with the weather. I heard of six inch hail in my state just a week or so ago.