“Derechos”

by Caleb, KE0FOE

As we continue with our series covering JetStream, The National Weather Service’s new Online School for Weather, the topic this time is: Derechos.

Derechos are widespread, long-lasting strong straight-line wind events associated with a band of rapidly-moving showers or thunderstorms.

“Derecho” is a Spanish word which means “direct” or “straight ahead”. This is in contrast to a tornado which comes from the Spanish meaning of “to twist or turn”.

There are three types of derechos: Serial, Progressive, and Hybrid. A serial derecho can be several hundred miles long and travel across a very large area both wide and long. Progressive derechos are shorter lines of thunderstorms with narrower paths than serial derechos.

Hybrid derechos share characteristics of both serial and progressive derechos.

The National Weather Service does not issue “derecho warnings” because derechos are wind events produced by severe thunderstorms. Therefore, any warnings for derechos will be part of a Severe Thunderstorm Warning.

The strength of a derecho can produce destruction similar to EF-0 and EF-1  tornadoes. However, the damage pattern produced by derechos occurs along relatively straight lines. That’s where the term straight-line wind damage comes from.

Derechos cause more fatalities than both EF-0 and EF-1 tornadoes combined despite the fact that EF-0 and EF-1 tornadoes make up more than 80% of all recorded tornadoes. Nearly half of all deaths caused by derechos happen either in vehicles or on boats.

There are a lot of interesting facts about Derechos that you and your family can learn about on the National Weather Service’s new Online School for Weather called JetStream. Visit their website: weather.gov/jetstream