Derechos

For a list of significant derechos that have occurred in West Virginia and detailed information about each, scroll to the bottom of the page.

It's the dreaded "D" word in West Virginia weather: derechos! This word strikes fear in some West Virginians due to the damage that they can cause. Most recently, the June 29th, 2012 derecho was one of the most widespread-producing severe weather events outside of flooding our state has ever seen.

What exactly is a derecho?

According to the Storm Prediction Center and the American Meteorological Society, a derecho is a widespread severe windstorm characterized by a family of destructive downbursts containing multiple 75+ mph gusts associated with an extratropical, cold-pool-driven mesoscale convective system.

There are a few criteria that must be met for a complex of thunderstorms to be classified as a derecho:

• Widespread severe wind reports (58+ mph gusts, measured or estimated)
• The complex (MCS) must be at least 60 miles long and last for at least 3 hours
• No more than 1 hour may elapse between reports in the wind swath
• The wind swath must be at least 250 miles long
• At least 5 75+ mph gust reports (measured or estimated), separated by 50 miles

More details on the classification and thresholds for derechos can be found here.

Derechos actually occur more often than we realize, it's just that most of them are not as severe as the 2012 storm that people in West Virginia typically think of when they hear the term 'derecho'. 

As you can see below in this graphic produced by the Storm Prediction Center, our area on average experiences a derecho every two years. That's fairly often when you think of it! Most of the time though, they're much weaker than the generational storm the Mountain State experienced in 2012.

The list below are the significant derechos that have occurred in West Virginia's history. All three of them are very different in nature and will be discussed in detail at the links below:

Significant Derecho Events in West Virginia

• June 29th, 2012 - The Ohio Valley/Mid-Atlantic Derecho of June 2012
• August 8-9th, 2000 - The Appalachian-Crossing Derechos of August 9-10, 2000
• April 9, 1991 - The West Virginia Derecho of 1991