WEATHER BLOG POST: What is a Microburst?
Thursday, July 14, 2016
AUGUSTA, Ga. (WRDW/WAGT) -- You’ve seen the headlines “Microbursts…Downbursts… Straight Line Winds... causing destruction during the summer months."
All these words may be synonymous of each other, but they are not synonymous with the word
. However, they can cause just as much damage as one!
A microburst happens within a thunderstorm. All thunderstorms have rising and sinking columns of air, called the updraft (rising motion), and the downdraft (sinking motion). Within the updraft, the core of the storm is located. Hail and water particles are collected in the core . However, when the updraft becomes “too heavy”, or weakens and can no longer contain the core of the storm, the core can come crashing down in the downdraft, spreading in all directions as it hits the ground, bringing violent wind speeds with it. The strongest winds will be where the downdraft initially landed.
Wind speeds of 100mph or more can be brought on by a strong microburst, that’s wind speeds equivalent to an EF 1 tornado!
With the damage we saw at Mistletoe State Park, we know that microbursts can be destructive. It’s understandable why many people thought this was damage done by a tornado. With wind speeds that strong, we are very lucky there were no serious injuries. That leaves many with the question…
Well, because a microburst event is almost virtually impossible to forecast, meteorologists look for key factors that promote favorable conditions for a microburst to take place. First and foremost, heat and humidity cause the atmosphere to be unstable, which is why microbursts are more common during the summer months. Hot and humid summer afternoons are key variables in microburst formation. Other atmospheric factors meteorologists use to better forecast the possibility of a microburst include examining where dry air and strong winds are located in the atmosphere, and how much precipitable water (depth of moisture in the troposphere) is expected. Microbursts are also pretty tough to depict on radar, but do have some active divergence signatures (winds pointing away from each other) on velocity.
Because of the difficulty level in forecasting microbursts, it is vital to pay attention to severe warned storms and thunderstorm watches, especially during summer months.