What are straight line winds

By: Meteorologist Paul Trambley

Updated: Mar 4th 2022

Each severe weather season, tornadoes, destructive hail, and straight-line winds wreak havoc across the U.S. All are dangerous, but of these, one is more likely to impact you than any other. This distinction belongs to straight-line winds. Straight-line winds are damaging winds that travel in a uniform direction as they propagate across an area. Some straight-line wind events can be so destructive that they are sometimes mistaken for tornadoes. However, there is a tell-tale sign that a damage path was caused by straight-line winds and not a tornado. When damaged trees and other structures are leaning in a uniform direction, the culprit is more than likely straight-line winds. On the other hand, tornadoes will inflict damage in paths that show its impact inflicted in varied directions due to the rotating winds found in a tornado. Straight-line winds can at times exceed 100 mph, while the winds in a tornado can top 200 mph. Tornadoes tend to keep their destruction confined to more localized areas, while straight-line winds tend to inflict damage on a much larger scale. For this reason, straight-line winds account for around 50% of all severe reports during any given year. Now that you know some of the statistics surrounding straight-line winds, let's dig into how this weather phenomenon forms.

Understanding the basic anatomy of a thunderstorm and the vertical wind currents that occur within is integral in gaining an understanding of how straight-line winds develop. When a thunderstorm develops, a localized rising current of air, known as an updraft heads skyward. At this point, an observer would notice a growing cumulus cloud. When adequate moisture is present at the surface and a favorable environment exists higher in the atmosphere, the cloud updraft will increase in velocity, and a towering cumulus cloud will be seen. As the thunderstorm matures, rain begins to fall to the ground. As the rain droplets fall, air is dragged downward with them. This downward directed current of air is known as a downdraft (the opposite direction of an updraft). Meanwhile, as the edges of the storm interact with dry air that is surrounding it, some raindrops evaporate. Because evaporation is a cooling process, the pocket of air where the raindrops have evaporated becomes cooler than the air surrounding it. Because cool air is more dense than warm air, this cooled pocket of air accelerates downward. It is these two processes that work together to create the downdraft portion of the storm. For a time the updraft and downdraft will co-exist in harmony, but at some point the updraft will get overtaken by the downdraft, and at that point the storm will fizzle out.

Now that you understand the basic structure of a thunderstorm, let's look at how this relates to the formation of straight-line winds. When the environment is favorable for strong thunderstorms, updraft and downdraft speeds can exceed 100 mph. Meanwhile, intense downdraft winds, also known as microbursts, drive down to the surface and then spread out. As the wind spreads out horizontally over the land, straight-line winds are experienced. The image below depicts this process as a microburst is shown accelerating to the ground and then spreading out horizontally, resulting in straight-line winds. As the wind travels across the surface it will at first be intense, but as it travels further, the effects of friction at the surface will slow it down. For this reason, damage from microbursts can be fairly localized at times.  However, during favorable atmospheric conditions, organized storm complexes can produce straight-line winds for 100's of miles. 

The safety protocol for straight-line winds is the same as you would follow for a tornado. This is because straight-line winds can uproot trees, toss various debris airborne, and cause damage to standing structures. For this reason, it is advised that you stay away from windows and go to the lowest level of a home or business. Always seek an interior room on the lowest level, which is typically a bathroom or hallway. If you have no access to a shelter, the best option is to seek an open area away from trees or other structures that may fall on you. So the next time you hear that straight-line winds are approaching, seek shelter and ride the storm out in safety.

For a visual on how a microburst can produce straight-line winds at the surface, click here. 

https://www.weather.gov/images/bmx/Daily/microbursts/microburst.jpg

When it comes to destructive weather systems, most people typically think of tornadoes or hurricanes, depending on where in the country they are located. However, there is another weather system capable of causing immense damage here in the United States — straight line winds.

Often confused with tornadoes, due to their ability to damage property, straight-line winds stem from non-rotating thunderstorms. These powerful winds shoot downward at high speeds, spreading outwards when they reach the ground, sometimes reaching as much as 100 mph. Although different than tornadoes, straight-line winds need to be taken seriously, especially by those who live in areas where they are prone to occur (straight-line winds are likely to form in the same locations where tornadoes are frequent).

Continue reading to learn everything you need to know about straight-line winds, including how they form, how they differ from tornadoes, and what you should do if they occur where you are located.

How are Straight-Line Winds Created?

Straight-line winds are caused by a difference in air temperature and density within a thunderstorm. When cool, dry air forms inside a thunderstorm, condensation and rain can continue to cool it until it eventually becomes heavier than the surrounding warmer air. This weight difference, paired with the shift in temperature and density, results in a sudden downburst of air. When the cool air reaches the surface of the Earth, it spreads outward, resulting in strong winds that can damage homes, vehicles, trees, and other structures.

Given the severity of the damage that can be caused by straight-line winds, if a straight-line wind warning is issued in your area, seek shelter as if it were a tornado. Basements, closets, and other interior rooms away from windows are some of the best locations in which to take shelter during straight-line winds. If you are unable to make it to any of these locations, getting under heavy furniture, such as a dining table, can help to protect you from broken glass or other falling objects.

What’s the Difference Between a Tornado and Straight-Line Winds?

As mentioned previously, straight-line winds are often confused with tornadoes. This is most likely due to the fact that they both feature powerful winds, can cause immense damage to properties, and tend to occur in similar locations throughout the country. However, despite their similarities, there are some key differences between straight-line winds and tornadoes.

Air Movement - To begin, tornadoes rotate, meaning air flows into them. Conversely, with straight-line winds, all of the wind comes from the immense downburst, pushing the air outward.

Debris Pattern - Another way to tell if an area has been hit by a tornado or straight-line winds is to look at the leftover debris. If it looks as if it has been thrown outward in a circular formation, it is probably a tornado. On the other hand, if the debris is linear, straight-line winds are more likely to be the culprit.

Can Straight-Line Winds Turn Into a Tornado?

Due to their similarities, many people wonder if straight-line winds can turn into a tornado. Because tornadoes are caused by rotating storms and straight-line winds come from thunderstorms that don’t rotate, straight-line winds do not typically turn into tornados. You are only likely to have one or the other depending on the weather system. Still, both are capable of endangering people and inflicting costly damage.

Cleaning Up After Storm Damage

If your property has been damaged by straight-line winds, contact the professionals here at BELFOR to help secure your property and prevent further damage from occurring. Our storm damage services include:

You can also consult our mobile app to contact the BELFOR location nearest to you, request immediate assistance, and receive helpful tips on how to minimize damage to your property. Don’t put your property at further risk. Contact BELFOR for effective storm clean-up and recovery services.

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When you think of damage from a storm, a tornado may come to mind.

Tornados are well known and discussed in the news frequently – they even star in movies! But did you know that there’s another wind-based storm you should have on your radar?

Read on to learn about straight-line winds and the intense damage they can cause.  

What Are Straight-Line Winds?

In order to explain what straight-line winds are, it’s first important to know what they aren’t. Straight-line winds are not tornados. To be classified as a tornado, the wind must rotate. It’s also important to note that straight-line winds are not your run-of-the-mill damaging wind (a catchall term used to define wind events under 50 miles per hour).

Straight-line winds are the result of a very specific weather pattern and exceed 50 miles per hour, potentially matching the wind speed – and damage – of a tornado.

What Causes Straight-Line Winds?

Also known as downbursts or convective wind gusts, straight-line winds are one of the rare by-products that can result from a strong thunderstorm. During a strong thunderstorm, it is sometimes possible for cool, dry air to build up inside the storm system. Over time, this pocket of air becomes much heavier than the surrounding warm air. The difference in weight, density, and temperature causes the system to push the dry air downward, towards the ground at a high speed in a microburst, creating a straight-line wind that fans out as it nears the surface of the earth. Straight-line winds may accelerate to a speed in excess of 100 miles per hour.

Straight-Line Winds vs. Tornados

Tornados that touch ground often destroy homes and commercial buildings, creating casualties. Straight-line windstorms are less likely to topple a building, but can still be very destructive as trees are knocked over, roofs are torn from houses and temporary or modular structures may be moved from their foundation.

In the moment, it can be very difficult to determine which type of wind event you’re experiencing – a straight-line windstorm or a close call with a tornado. Without first-hand accounts of the tornado-shaped funnel, it’s often up to the damage itself to tell us what type of weather system just rolled through.

Damage from a straight-line windstorm is easy to identify, especially from the sky. After a straight-line wind, the damage will show a straight swath of damage. This is particularly apparent in forests and wooded areas, where straight-line winds make downed trees look like toothpicks all knocked over in the same direction for miles across.

Protect Your Home From Straight-Line Winds

Though they rarely collapse buildings, it’s important to note that straight-line winds can be just as dangerous and damaging as some tornados.

Because they can be caused by thunderstorms, anyone living in a thunderstorm-prone area is at risk for experiencing this threatening weather pattern.

Make sure you and your home are prepared should straight-line windstorms hit your area:

Loose items in your yard can turn into projectiles during a severe wind event, including tables, chairs, children’s toys, gardening equipment, and fallen tree limbs.

Stay on top of yard maintenance tasks including tree trimming. Low-hanging branches and dead limbs may become battering rams in high winds. Avoid damage to your home by hiring a professional like The Grounds Guys to maintain your home’s landscaping.

Inspect your roof annually and after any major storms. Keep an eye out for small holes, loose shingles and damage to gutters and eaves.

• Keep Your Emergency Kit up to Date

Just like a tornado or a severe thunderstorm, straight-line winds can damage utilities like power lines and knock over trees, blocking roadways. Be prepared by stocking an emergency kit with everything your household may need for at least three days. 

• Know Your Homeowners Insurance Policy

Familiarize yourself with your home insurance policy or renter’s insurance policy. Make sure you understand what is and is not covered – especially as it pertains to accommodations should your home be damaged by straight-line winds. Purchase additional coverage if necessary.

We Make Disasters Disappear

Like tornados, blizzards, earthquakes, and other natural disasters, we can’t prevent but we can prepare and recover. Taking steps towards maintaining your property, year-round, and keeping a stocked emergency preparedness kit will help you face any storm, head-on.

Should your property fall victim to a natural disaster, choose Rainbow International for restoration, remediation and full-service reconstruction services (where available) designed to get you back to normal, fast.

Don’t wait, call (855) 724-6269 today or request an appointment online to get started.

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