What is a microburst? Everything to know

After a drier and hotter than usual trend hit Arizona mid-summer, the state has been getting a wetter end to the monsoon with thunderstorms, hail, strong winds and heavy downpours — as well as microbursts— ripping through parts of the Valley.

In Arizona, you may have seen a microburst without knowing what it was. In a nutshell, this phenomenon is a column of speeding air expulsed over a small area that occurs when a pocket of cold air develops inside a thunderstorm.

Colder air is more dense. When that pocket of air is concentrated enough, it becomes heavier than the air around it, making it drop like a bomb; usually over an area smaller than 2.5 miles in diameter.

According to the weather service, microbursts can generate winds of up to 150 mph and cause more damage to the surface than a tornado, and in some cases, they can be life-threatening.

Here's everything you need to know about the intriguing weather occurrence and how to stay safe.

Are microbursts common in Arizona?

Microbursts happen quite often in the state, said Alex Young, meteorologist with the National Weather Service in Phoenix.

"With any thunderstorm activity, especially during the monsoon season, a downburst or microburst type of situation is a common occurrence," he said.

Microbursts can also come with heavy rain and sometimes hail, which is called a wet microburst. In Arizona, dry microbursts are the most common type, Young said, but more wet microbursts can be seen during the summer months.

What happens during a microburst?

Every thunderstorm forms with an updraft and a downdraft, according to Young. The updraft works at the engine of a thunderstorm by rapidly pulling in moisture, and the downdraft is where precipitation falls from the storm.

Young said during a microburst, the moisture and air pulled in by the updraft get more dense as they are pulled upward. The updraft then will get to a point in which it condenses into water droplets and sometimes hailstones that get suspended in the upper portions of a thunderstorm.

As the updraft continues to bring more water that later condenses, the updraft weakens, at which point it is no longer capable of holding the concentrated air and water up in the storm, causing that core to plummet to the ground.

In a dry environment, like in Arizona, those water droplets are likely to evaporate back into the storm. That evaporation cools the air, intensifying the downdraft's impact on the ground.

"That's why typically in Arizona, dry microbursts are a little more common, and they can be very impactful, because this evaporative-cooling process will accelerate that downdraft to make it stronger," Young said.

How long do microbursts last?

The initial strong push of winds can last anywhere from 5 to 20 minutes, Young said. The gusty winds that linger in the area can last for up to an hour, he said.

"Really, that initial push is typically the worst, since that'll be the strongest winds when a microburst occurs," Young said.

What are the dangers of a microburst?

The greatest threat that can come with a microburst is the wind, Young said.

Even if an area is not directly impacted by a microburst, Young said the winds that come down on the spot will spread out to nearby areas, bringing strong, gusty winds.

Even after the winds have hit the ground, they can spread with speeds of about 60 mph, Young said, although that can vary depending on the strength of the downburst and moisture levels, among other conditions.

Damages in areas directly impacted by the initial shot of air can be far more severe, according to the weather service. Wind speeds in a microburst are equivalent to an EF1 tornado and can inflict significant harm to residences and topple a multitude of trees in a matter of minutes.

The weather service advised residents to take severe thunderstorm warnings as seriously as tornado warnings.

Both types of microburst, wet and dry, generate strong winds, and both can be just as dangerous, Young said.

However, the impacts can be different. Some other hazards that can come with wet microbursts are hail and heavy rain downpours, which can potentially increase flood risk. On the other hand, dry microbursts can also produce localized blowing dust on top of accelerated winds.

"Especially if you have a complex of thunderstorms, and all the microbursts combine together, that can push out a swell of dust that usually ends up getting into the Phoenix metro from south and eastern Arizona," Young said.

What are the signs a microburst will happen?

Although microbursts are hard to predict and they happen quickly, people in an area near a thunderstorm can see a downburst coming if they see concentrated downpours off the distance.

"That's a way you can observe the weather and at least try to get a sense of something potentially happening in your area in terms of a microburst," Young said.

According to the weather service, the ideal conditions typically come together during hot and humid summertime afternoons.

Young advised residents to check the weather frequently and stay aware of thunderstorm activity.

This article originally appeared on Arizona Republic: Arizona weather: What is a microburst? Everything to know