Explained: What is a derecho, a storm that turned the sky green in the US?
The states of Nebraska, Minnesota and Illinois in the US were hit by a storm system called Decho on Tuesday. When the storm rolled, the wind blew around 140 km per hour, yelled at the electricity channel and knocked down trees. When the storm hit, it changed the sky to green, with even many experienced storm hunters who claimed to have never witnessed such an atmospheric optics, according to the Washington Post. What is Decho, how to change the US sky to be green?
What is a derecho?
Derecho, according to the US national weather service, is a “extensive straight line, long -lived wind” which is associated with “shower bands or thunderstorms that move quickly”. The name comes from the word Spain ‘La Derecha’ which means ‘straight’. Straight Storms are the ones where the storm has no rotation unlike tornado. This storm takes hundreds of miles and covers a large area.
Being a phenomenon of warm weather, Dereko generally-not always happening during the summer starting in May, with most of the hitting in June and July. However, they are rare events compared to other storm systems such as tornado or storm.
In order for the storm to be classified as Decho, he must have a gust of wind at least 93 km per hour; Damage to the plot extends more than 400 km. According to the Oklahama University Meteorology School, the time gap between sequential wind damage events should not be more than three hours.
Why did the sky turn green during the derecho that hit US recently?
Severe lightning storms produce ‘green sky’ because of the light that interacts with a large amount of water they hold. A report at The Washington Post said that it is believed that the rain and hail spread all except the blue wavelength because the blue light penetrates under the storm clouds. This blue is then combined with the afternoon red yellow or night sun to produce green, the report said.
Are there various types of derechos?
They are included in three categories – progressive, serial and hybrid. A progressive
Decho is associated with a short line of lightning storms that can travel hundreds of miles along a relatively narrow road. This is a summer phenomenon.
The Serial Decho, on the other hand, has a large squareline – width and long – sweeping in a large area. Usually occurs during spring or autumn.
Where do Derchos usually occur?
They mostly occur in the middle and eastern of the United States.
“Super Derecho” May 8, 2009 is one of the “most intense and unusual derechos ever observed” in the US when sweeping Kansas to Kentucky with wind speeds reaching up to 170 km/hour.
Derchos has also been documented elsewhere throughout the world. In 2010, Russia watched Derecho who was first documented. They also swept Germany and Finland, and recently in Bulgaria and Poland.