NBC News (http://www.click2houston.com/news/10841661/detail.html)
ABC News (http://abclocal.go.com/ktrk/story?section=local&id=4969534)
Houston Chronicle (http://www.chron.com/disp/story.mpl/metropolitan/4497976.html)

The other night, I was on the phone with a buddy making preparations to dream about just this sort of thing. He lives about a quarter mile from the demolished house. I heard a rumble through the phone, and he got quiet. He said the blast shook his house. It's amazing to me that the house is completely flattened, except for the chimney.

It's kinda humorous, considering nobody got killed. Reminds me a little bit of Fight Club with the natural gas leak and without the homemade TNT. Do you think grandma blew it up for the insurance money?:D

"You would think with the blast coming from across the street it would send the stuff into the home but it fell outward," she said.

Yeap it looks like aerosol explosion from that backblast description...methane or coal dust from the chimney are my starting theories.