The Mysterious Thud

I've lived in this lovely house for over six years now. I'm not sure precisely when this started happening, but my best memory of a beginning is sometime after Hurricane Rita.

One calm, sunny day I was peacefully sitting in my home, minding my own business, when there was this loud BOOM! and the house quivered seemingly down to its foundation. Something must have hit the roof. I rushed outside and carefully studied the back of the house, where my trees are. All three of them were right where they belonged, no limbs missing, enjoying the sunshine.

After scratching my head, I headed to the front yard, where there are no trees, on the off chance that something truly weird had caused a limb to plop down on my house. Nothing.

Next stop? Move the car out of the garage so I could get a look at the attic. Nothing extraordinarily weird up there, even though there is weird stuff in the attic.

OK. Must be imagining things. Got my local handyperson to come and give things a look. He scratched his head, too, and decided it was nothing to worry about.

Over the years since then, I've heard this mysterious thud multiple times. No rhyme or reason to its occurence, except that it's always been during the day, generally in the afternoon, and the weather has been of the sort that doesn't lend itself to loud booms. Each time, I've rushed outside, scanned the roof and surrounding yards, scratched my head in befuddlement, and gone back inside.

Then there was today.

KABOOM! The house shuddered. Contrary to my usual approach, I ran out the front door to look at my roof and up and down the street. I wasn't the only one standing in my front yard looking perplexed. The gentleman two houses down said, "Did you hear that?! Do you see any trees down?" We both scanned the nearby houses and horizon. No down trees.

I said, "I'm going to check the back of the house!" He said, "Me too!"

We both ran through our houses and began looking at our homes and at the nearby houses. No down trees. We both shrugged, then went back into our respective houses.

At least I now know it's not my house that has a problem.

But just what is that mysterious thud?