The severe storm season is upon us. Wind storms this past Monday night were especially violent in some areas, prompting many people to make claims on the order of, "It must have been a tornado, because straight-line winds can't do that kind of damage." It's true that violent tornadoes, those rated EF4 and EF5 such as the 1957 Fargo tornado, with wind speeds greater than 165 mph, are capable of greater damage than virtually any non-tornadic thunderstorm wind. However, this represents a very small percentage of all tornadoes.
Non-tornadic thunderstorm winds are extremely turbulent. Shearing wind forces can cause considerable damage, some of it clearly caused by twisting and some of it quite catastrophic. About 85% of all tornadoes produce winds of 65-110 mph, which is on par with what is found within some of our more violent Northern Plains thunderstorms.