Sometimes when flying a plane, a pilot may encounter wind shear. What does it mean when a pilot faces this natural weather phenomenon? Discover what wind shear is and the factors that contribute to its formation.
What is Wind Shear?
Most of the time, we encounter the term ‘wind shear’ when thinking about aviation, but did you know that wind shear plays a role in the development of tornadoes? Were you aware that wind shear can tear hurricanes apart, thereby reducing their overall strength? Wind shear also helps wind turbines spin around and around at top speeds.
This type of wind shear travels at different heights or in a vertical direction. When you see a strong thunderstorm rolling through, you can thank vertical wind shear for influencing such conditions. That is, during a vertical shear, the change in winds at this given height impacts (and can even diminish) the strength of a thunderstorm. This type of wind shear can influence both changes in wind direction and in speed.
This type of wind shear occurs over a horizontal distance, usually influencing directional changes. A plane might encounter horizontal wind shear when flying near mountainous areas or when passing directly through a front. A front is simply a boundary between two different masses of air in the atmosphere. These air masses can be either cold or warm.
What Causes Wind Shear?
One not-so-pleasant side effect of a thunderstorm is the production of wind shear. In a thunderstorm, you will often see wind shear in the vicinity of a microburst. Microbursts are really small yet intense downbursts that can lead to the formation of hazardous vertical and horizontal wind shears.
Think of a downburst as a fast-moving air current that flows in a downward direction. During a downburst, air will rush towards the surface of the ground at a high speed and spread out in all directions.
Sometimes, the speed at which it spreads can be over 100 mph. Because wind is spreading in different directions and at varying speeds, it is common to experience wind shear near these downbursts.
Have you ever walked outside only to notice that it is hazy? When catching a sunset, have you ever witnessed a sun that looks very red as it begins to set? Both of these phenomena are often caused by temperature inversions. Temperature inversions occur when the temperature of the air gets colder as you get closer to the surface of the earth. In normal cases, air near the surface of the earth is a lot warmer than the air above it. Typically, overnight cooling causes temperature inversions.
If this takes place in conjunction with high winds (what meteorologists call a ‘jet stream’), wind shear can form very close to the ground.
Wind encounters a lot of obstacles. These obstacles range from tall buildings to hills to a forest of trees.
Sometimes, wind shear is formed when the wind must flow around these types of obstacles. Depending on how fast the wind is flowing and the angle at which the wind hits the obstacle, the severity of wind shear can vary.
Wind shear is the change in speed and direction of wind over a short distance. It is most often caused by microbursts from thunderstorms, temperature inversions, and surface obstructions. There are two different types of wind shear patterns: horizontal and vertical. Commonly, pilots must pay close attention to wind shear as they navigate aircraft.