Another Explosive event

My wife was working with the computer in the library, I was reading in the den which is next to the library. Our dogs were sacked out, one at the foot of my wife's chair and the other in front of the TV in the den. A crash sounded, it shook the house. It sounded like something had come through the roof. It got our attention quick enough and both dogs ran barking to the kitchen. It was misty, icy, and wet outside. I didn't check outside. Frankly it sounded like something had fell through the roof. I checked all rooms on the first and second floor and in the attic. Everything was fine. Today, I checked outside and there was no sign of anything on the roof or near the house. No ice was built up on the roof. I'm happy I can't find damage; but what on earth are we hearing that leaves no trace.