Several states in the US were hit by a storm system called a derecho on July 5. As the storm rolled in, winds gusting at around 140 km per hour, snapped power lines and knocked down trees.
- As the storm hit, it turned the skies green.
What is a derecho storm?
- A derecho is a widespread, long-lived, straight-line windstorm that is associated with a band of rapidly moving showers or thunderstorms.
- The name comes from the Spanish word ‘la derecha’ which means ‘straight’.
- Straight-line storms are those in which thunderstorm winds have no rotation unlike a tornado.
- Being a warm-weather phenomenon, a derecho generally – not always – occurs during summertime beginning May, with most hitting in June and July.
- However, they are a rare occurrence as compared to other storm systems like tornadoes or hurricanes.
- For a storm to be classified as a derecho it must have wind gusts of at least 93 km per hour; wind damage swath extending more than 400 km.
- The time gap between successive wind damage events should not be more than three hours.
Green sky
- The green sky that comes with some severe thunderstorms has to do with what the thunderstorm is holding — water, and lots of it.
- It’s believed that big raindrops and hail scatter away all but the blue wavelengths, allowing primarily blue light to penetrate through and beneath the storm cloud.
Derecho categories
- Derecho falls into three categories – 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. It usually occurs during spring or fall.
GS TIMES UPSC PRELIMS & MAINS CURRENT AFFAIRS BASED BASICS DAILY ONLINE TEST CLICK HERE
CLICK HERE DAILY CURRENT AFFAIRS QUIZ FOR STATE CIVIL SERVICES
MORE THAN 30 QUESTIONS FORM GS TIMES UPSC 2022 PRELIMS CURRENT AFFAIRS DAILY TEST
