Bentonville Damage Not From Tornado

The National Weather Service has completed their survey of the damage that occurred during last nights storms from northern Bentonville. The significant tree damage was confirmed by the National Weather Service to be from a microburst, not from a tornado. We talked with the National Weather Service late this afternoon and they mentioned the trees and damage pattern was all in one direction, among other factors that lead them to confirming the microburst. The National Weather Service also mentioned to us that the wind speeds were estimated to be around 70 mph during the event.

Here is some video from a microburst in Canada caught on camera.

Here is a diagram from the National Weather Service showing how a microburst works.

downburst

The full link can be found below:

http://www.srh.noaa.gov/jetstream/tstorms/wind.htm

Differences Between Microbursts and Tornadoes

Tornado: Winds between 65 mph to 200 mph + (strongest recorded tornado, 318 mph)

Attached to cloud base, near updraft region of storm, damage path is convergent or circular in nature

Microburst: Winds between 50 mph to 100 mph + (strongest recorded downburst, ~120 mph)

many times occurs near shelf cloud, occur in the downdraft region of storm, damage path is divergent in nature.

Downbursts, Macrobursts and Microbursts Defined

Downbursts are divided into two categories; macrobursts and microbursts. A macroburst is more than 2½ miles (4 km) in diameter and can produce winds as high as 135 mph (215 kph). Microbursts are smaller and produces winds as high as 170 mph (270 kph).

In wet, humid environments, macrobursts and microbursts will be accompanied by intense rainfall at the ground. If the storm forms in a relatively dry environment, however, the rain may evaporate before it reaches the ground and these downbursts will be without precipitation, known as dry microbursts.

Ross Ellet

Advertisements

6 Responses

  1. I was listening to the scanner last night and heard a spotter report quarter size hail near Siloam Springs early in the evening. The Tulsa weather service acknowledged the report but did not issue a warning for Benton County at the time. Do you know why the weather service would disregard a report from a spotter?

    • I remember the report when those storms developed along an outflow boundary in western Benton county. I don’t want to answer for the Weather Service, so I can’t really say.

      Drew Michaels

  2. I still miss the good ole days when the weather service in Fort Smith was in charge of our warnings. They seemed to be more concerned about Arkansas weather than Tulsa is.
    Just my humble opinion. 🙂

    • Mike I want to hope your experience with Tulsa was an isolated incident. I have been able to get to know some of the guys over there and they are very dedicated in training folks in our area. I always appreciate you reading and making comments on the blog!

      Drew Michaels

  3. Wow! what an idea ! What a concept ! Wonderful .. Awesome …

  4. wow!wonderfull……..what and awsome idea

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s

%d bloggers like this: