Severe Weather Preparedness Drill, Straight Line Wind Damage Explanation (English)

Straight Line Wind Danger

Severe Thunderstorms producing straight line wind damage can be dangerous.

Severe Thunderstorm Warnings are issued when wind speeds reach 58 mph or higher. Here is an example of the type of damage that can occur in such winds

Most businesses and homes will not sustain damage in such winds. However damage from other objects, such as trees or powerlines can occur and be dangerous. For instance, what if you were driving down the road on the lower left image when those power lines fell? Unanchored mobile homes can also be damaged or destroyed by such winds.

Stronger storms can produce straight line winds of 70 to 80 mph, especially in localized downburts or microbursts. Wind speeds at those value can do damage like this

Most homes and businesses will again not suffere significant structural damage in such winds, but significant exterior damage can occur, such as damage to roofs, awnings and siding. Lesser built buildings such as sheds and outbuildings can suffer significant structral damage or be destroyed in such winds.

The strongest storms, such as the one in our drill, can produce wind speeds of 90 mph or higher. This will do significant damage.

In winds this strong most mobile homes will be seriously damaged or destroyed. Many businesses and some homes, especially those that are older will sustain at least some roof damage and some of it may be significant. If the storm is also producing large hail, as it did in McAllen on March 29, 2012 significant and widespread damage can occur from wind driven hail. Obviously, numerous trees and powerlines will be knocked down in addition to all of the damage previously mentioned at lower wind speeds. Damage at these wind speeds will be very similar to that of an EF0 or EF1 tornado.

An EF2 tornado produces winds of 111 to 135 mph and will do more extensive damage.

Significant structral damage can occur to the exterior of homes, including having their roofs completely removed. Mobile homes will be completely demolished and numerous businesses will sustain significant damage such as partial or complete roof removal, awnings will fail and outdoor signage will be destroyed.

There are two key facts to remember when it comes to the dangers of severe thunderstorm and tornado winds:

1. There are places that are dangerous in any severe thunderstorm, such as cars and mobile homes.

2. There are places that are relatively safe in most all severe thunderstorms, such as an interior room on the lowest floor of a well built home or business.

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