A derecho is a widespread, long-lived wind storm that is associated with a fast-moving line of thunderstorms. Derechos (pronounced de-REY-cho) are characterized by strong winds, including gusts greater than 58 miles per hour (93 km/h), and can produce widespread damage. They often cause damage to trees, power lines, and buildings, and can also lead to injuries or fatalities.

How do derechos form?

Derechos form when a line of thunderstorms, known as a squall line, becomes organized and develops into a long-lived system. This typically occurs when there is a strong difference in temperature and humidity between the warm, moist air ahead of the squall line and the cooler, drier air behind it. The rising warm air creates updrafts that can reach up to 10 miles (16 km) into the atmosphere, and the downdrafts that follow these updrafts can produce strong winds.

Where do derechos occur?

Derechos can occur anywhere in the world, but they are most common in the Great Plains and Midwest regions of the United States, as well as in Argentina, Uruguay, and Bangladesh. They typically occur in the summer months when the air is warm and humid.

What are the hazards associated with derechos?

The strong winds associated with derechos can cause widespread damage, including:

- Damage to trees and power lines, leading to power outages

- Damage to buildings, including roofs, windows, and siding

- Injuries or fatalities from flying debris or downed trees

How can you stay safe during a derecho?

If you are caught in a derecho, there are several things you can do to stay safe:

- Stay indoors and away from windows

- Take shelter in a basement or low-lying area if possible

- If you are in a vehicle, pull over to the side of the road and stay inside

- Be aware of the risk of downed trees and power lines after the derecho has passed