From the Houston Chronicle:
A five-alarm, windswept fire that destroyed a $50 million luxury apartment building under construction in Montrose on Tuesday may have been sparked by a welder, a fire department official said.
"There was a report of a couple of guys working on the roof doing welding," said Houston Fire Department Deputy Chief Greg Lewis. "When our units arrived, there was a small fire and construction workers were attempting to put it out. There was sustained wind of 15 to 20 miles an hour, and it was a wind-driven fire."