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Current Affairs 2023

Derecho - UPSC Current Affairs

A Derecho is a widespread, long-lived, straight-line windstorm associated with a band of rapidly moving showers or thunderstorms.

May 02, 2023

2 min read

Last year, some parts of the United States experienced a rare weather phenomenon called a Derecho, which turned the sky green.

A Derecho is a widespread, long-lived, straight-line windstorm associated with a band of rapidly moving showers or thunderstorms.

The name Derecho comes from the Spanish word 'la derecha,' which means straight, indicating that the winds move in a straight line and do not rotate like a tornado.

These storms are a warm-weather phenomenon that generally occurs in June and July, making them a rare occurrence as compared to other storm systems like tornadoes or hurricanes.

Derechos mostly occur across central and eastern parts of the United States, but they have also been reported in other countries like Russia, Germany, Finland, Bulgaria, and Poland.

Derechos come in three different types: progressive, serial, and hybrid.

A progressive derecho is associated with a short line of thunderstorms that may travel for hundreds of miles along a relatively narrow path. It is a summer phenomenon.

A serial derecho, on the other hand, has an extensive squall line – wide and long – sweeping across a large area, and it usually occurs during spring or fall.

Hybrid ones have the features of both progressive and serial derechos.

The most intense and unusual derecho ever observed in the US was the "Super Derecho" in 2009. It swept from Kansas to Kentucky with wind speeds reaching up to 170 km/hr. The storm caused widespread damage, power outages, and disrupted air travel.

One of the fascinating things about Derechos is that they can turn the sky green. Severe thunderstorms result in a 'green sky' due to the interaction of light with the massive amount of water they hold. The big raindrops and hail scatter away all but the blue wavelengths, primarily blue light penetrates below the storm cloud. This blue then combines with the red-yellow of the afternoon or the evening sun to produce green.

In conclusion, Derecho is a rare and powerful weather phenomenon that occurs in warm weather, mostly in central and eastern parts of the United States. The storms come in different types, including progressive, serial, and hybrid. Derechos can cause widespread damage, power outages, and turn the sky green due to the interaction of light with the massive amount of water they hold.