Sure would be nice if everyone would say where the heck they're located because knowing the kind of weather you have helps to answer many questions.
I'll guess your house has dried out from lack of proper humidity since you're well into the heating season. The wood, both floor and house, has shrunk and it snapped all at once. There may not be enough expansion gap around the perimeter. Sometimes the floor buckles and is lifted up a foot or even higher. It happens with tile floor too. It's called tenting.
So, it can be a combination of not enough moisture and/or improper installation.