One thing straight-line winds and tornadoes have in common is both pose a significant threat to both property and lives. While tornadoes are more well-known and have a reputation for destruction, straight-line winds can even be stronger and cause damage over a significantly larger area than that of a tornado.
It might come as a surprise to many people, but non-tornadic straight-line winds are extremely powerful, and in fact, can create a larger area of damage with winds stronger than some tornadoes.
According to the US government’s National Severe Storms Laboratory (NSSL), damaging winds, are often called “straight-line winds” as a term to differentiate them from the damage they cause versus that of a tornado.
During most thunderstorms, brief gusts of wind are an inevitable byproduct. Straight-line winds are formed as a result of thunderstorm downdrafts, which push wind straight down to the ground, which then outflows in each direction. Winds that exceed 50-60 miles per hour are classified as damaging winds. Straight-line wind speeds can reach up to 100 miles per hour.
In the lower 48 US states, half of all reports of damage that occurs in severe thunderstorms are a result of damaging straight-line winds. While tornado damage tends to occur in an isolated path, straight-line wind damage can be widespread, extending for hundreds of miles.
Tornadoes differ from straight-line winds in that they are comprised of a swirling column of air. This column of air tends to travel across ground in a narrower path, only affecting a fraction of an area.
tornadoes are rated by the “EF” scale, which stands for Enhanced Fujita scale (EF-scale), a method used for rating the intensity of tornadoes in the United States and Canada based upon the damage they create. It considers both the wind speed and potential damage levels.
Windspeed: 65-85 miles per hour.
Potential damage: Minor damage.
Windspeed: 86-110 miles per hour.
Potential damage: Moderate damage.
Windspeed: 111-135 miles per hour.
Potential damage: Considerable damage.
Windspeed: 136-165 miles per hour.
Potential damage: Severe damage.
Windspeed: 166-200 miles per hour.
Potential damage: Devastating damage.
Windspeed: Over 200 miles per hour.
Potential damage: Colossal damage.
While tornadoes tend to toss debris around randomly, straight-line winds, as their name would imply, tend to push things down in a single direction or in a fan-like pattern over a considerable distance.
It is these debris patterns found following a severe storm that experts examine in determining whether the damage that occurred was the result of a tornado or whether it occurred from straight-line winds.