What are straight-line winds and how do they form

Wind is one of the most common weather conditions. Normally it's nothing to worry about, but when it reaches high speeds it can be extremely devastating.

Damaging wind from thunderstorms is much more common than damage from tornadoes.

In fact, many confuse damage produced by straight-line winds and often erroneously attribute it to tornadoes.

There are a few reasons for that:

  • Tornado winds range from 40 to over 300 mph. Straight-line winds can exceed 165 mph.
  • Wind speeds of 75+ MPH will often sound very loud - leading some to believe they heard a tornado when if fact they only heard a straight-line wind.
  • Trees that appear to have "twisted" off were not necessarily done by a tornado.


How straight-line winds are formed

As air rises, it will cool to the point of condensation where water vapor forms tiny water droplets, comprising the cumulus cloud we see. As the air continues to rise further condensation occurs and the cloud grows. Near the center of the updraft, the particle begin to collide, forming larger droplets. This continues until the rising air can no longer support the size of water drops and it falls to the ground as rain. As the rain falls it begins to evaporate some which cools the air down and causes it to fall.



Cold air is heavier and more dense than warm air.

As the colder air hits the surface, it fans out and wind speeds can reach over 100 mph. The damage can be similar to a tornado, but the trained eye will notice damage from straight line winds will all fall in the same direction, whereas tornado damage will be scattered in all different directions.
Copyright © 2019 WTVD-TV. All Rights Reserved.