Houstons commercial building regulations call for structures to withstand three-second bursts of at least 100 mile-an-hour winds, according to local engineering firms. Newer skyscrapers, including many built during Houstons downtown boom in the 80s, were modeled in wind tunnels to determine their performance in extreme weather events. Most should survive the storm.
The last time downtown Houston saw extensive damage was during Hurricane Alicia, a Category 3 storm that hit in 1993. Roofs that were anchored by gravel turned into missiles in high winds. Now roofs, are held by strong concrete that should not blow off.
http://blogs.wsj.com/stormtracker/2008/09/12/deserted-downtown-houston/trackback/
alicia in 1983, nt 1993.