Three-second gusts from a tornado at 228 mph but ranging from 190-290 could be expected to cause significant strucutal deformation to 20+ story highrises. There are obvious differences between hurricanes and tornados but this would suggest that substantial damage to older high-rises is possible with a strong category 4 or category 5 landfall.
Source page http://www.spc.noaa.gov/faq/tornado/ef-scale.html
The page also has damage at different wind speeds for 28 other types of strucutes.
