Derechos Explained: How to Prepare for These Destructive Storms

This blog post explains what a derecho is, how these powerful storm systems form, the different types and notable historical events, and practical safety measures you can take.

Drawing on decades of meteorological observation and recent high-impact events, I break down the science and risks of derechos so readers in vulnerable regions can better understand and prepare for these fast-moving, destructive windstorms.

Table of Contents

What exactly is a derecho?

Derechos are long-lived lines of thunderstorms that produce extreme straight-line winds, often exceeding 60 mph and sometimes approaching hurricane-force gusts.

Unlike isolated tornadoes, derechos produce widespread, continuous swaths of damage that can extend for hundreds of miles and persist for many hours.

The impacts can be comparable to tornadoes or hurricanes in terms of wind damage, but the pattern and scale of destruction are different.

Tornado damage is usually narrow and concentrated, while derecho damage is broad and linear.

Types of derechos and how they form

Derechos develop in hot, humid, unstable air masses where strong upper-level winds — often associated with the jet stream — help organize storms into long-lived lines.

They commonly form near the northern edge of heat domes, where intense surface heating and ample humidity (sometimes enhanced by crop transpiration, such as from cornfields) increase atmospheric instability.

There are three main categories:

Progressive derechos — more common in summer, they form as a relatively narrow, intense line of storms that moves rapidly.

Serial derechos — often seen in spring, fall, or early winter, these are associated with large-scale frontal systems and can produce very long swaths of damage.

Hybrid derechos — combine characteristics of both types and can produce embedded small tornadoes in addition to straight-line winds.

Why they are especially dangerous

Derechos are hazardous because they can transition from calm to life-threatening conditions within minutes and affect very large areas simultaneously.

Whole communities can lose power, sustain structural damage, and be left with downed trees and blocked roads, making emergency response difficult.

Heavy rainfall and flash flooding can also accompany derechos.

Notable derecho events

Several U.S. derechos have left long-lasting impacts:

The 2003 southern derecho killed two people and caused widespread destruction.

The 2009 “Super Derecho” produced catastrophic damage exceeding $500 million in insured losses.

The August 2020 Midwest derecho struck near Cedar Rapids, Iowa, with winds close to 100 mph and destroyed roughly 100,000 trees, devastating urban and agricultural areas.

In December 2021 a derecho across the Great Plains and Upper Midwest spawned 45 tornadoes, killed at least five people, and caused extensive damage across multiple states.

Historically, derechos have also caused deadly flooding — in 1969 Ohio floods tied to a derecho killed at least 24 people.

How to stay safe during a derecho

Preparation and timely information are critical.

I emphasize the importance of monitoring forecasts and acting quickly when warnings are issued.

Recommended safety steps include:

Monitor weather alerts: Use NOAA Weather Radio, smartphone alerts, and local media for warnings and updates.

Seek sturdy shelter: Move indoors to an interior room away from windows; basements or reinforced rooms are best.

Have an emergency kit: Include water, food, flashlights, batteries, first-aid supplies, and a battery-powered radio.

Plan for power outages: Secure loose outdoor items and have alternate power or communication plans for critical needs.

Know evacuation routes: If flooding or debris blocks roads, have multiple ways to reach safe locations.

Final thoughts

Derechos are among the most rapidly-evolving and wide-ranging severe wind events we face.

Understanding their triggers — heat domes, humid air masses, and strong jet stream dynamics — helps communities prepare and reduce harm.

When conditions are ripe for organized severe storms, stay informed and ready to move to safe shelter within minutes.

Here is the source article for this story: What you need to know about derechos, an uncommon and destructive weather event