Sunday, March 29, 2015

Tornado in outskirts of Chennai on September 2013


A tornado is a violently rotating column of air that is in contact with both the surface of the earth and a cumulonimbus cloud or, in rare cases, the base of a cumulus cloud. They are often referred to as twisters. Tornadoes come in many shapes and sizes, but they are typically in the form of a visible condensation funnel, whose narrow end touches the earth and is often encircled by a cloud of debris and dust. Most tornadoes have wind speeds less than 180 km/h. Most extreme tornadoes can attain wind speeds of more than 480 km/h. The scale of intensity for Tornado is given below.


Tornado in India

The areas of  occurrence of tornadoes in India are given in fig below. About 72% of the reported tornadoes in India have occurred in northeast India and Bangladesh.


About 76% of the tornadoes in India occur during March to May, the most favored month being April (see fig below) More number of tornadoes have occurred in the afternoon and evening. 72% of tornadoes are associated with “KalBaishakhi”.



F-3 Tornado in Odisha on March, 2009

During noon of 31st March 2009, A Tornado ravaged Odisha, a high winds damaged the villages in a narrow track of about 600 metres wide upto 6 kilometers long from the origin. The intensityof the tornado increased gradually and was maximum over Baghabuda. The tornado also passed over the water bodies like ponds in the villages, as fishes weighing 1-2 kg were found scattered. The photo of the the Tornado was put up in Odisha Diary.




It was an F-3 category Tornado, you can see the funnel upto the surface. It caused huge devastation and loss of life in Odisha. Lets now see Chennai's Tornado in 2013.

Possible F-0 Tornado in outskirts of Chennai September, 2013

There is some disagreement over the definition of funnel cloud and condensation funnel. According to the Glossary of Meteorology, a funnel cloud is any rotating cloud pendant from a cumulus or cumulonimbus, and thus most tornadoes are included under this definition. Among many meteorologists, the funnel cloud term is strictly defined as a rotating cloud which is not associated with strong winds at the surface, and condensation funnel is a broad term for any rotating cloud below a cumuliform cloud.

Chennai's Twister

So what was is it in Uthandi in outskirts of Chennai was it only a funnel cloud or did it have surface winds from the funnel cloud. The day was September 12, 2013, and the time was 4.30 pm. Robert Gagarin (58) of Uthandi happened to be on the rooftop of his house in time to catch a glimpse of a tornado in the distance.
“The sky turned pitch dark and I saw a circular cone shaped cloud formation for about 15 minutes. I clicked some pictures and also a video with my smart phone,” says an excited Robert according to Deccan Chronicle.

IMD Chennai's View

Met officials confirmed that Robert Gagarin had indeed seen a tornado, the first one reported in Chennai. “Our officials, who were on their way to Puducherry too experienced some effects of this phenomenon but we confirmed it only after seeing the picture” Dr Y.E.A. Raj, Deputy Director General of Meteorology, Regional Meteorological Centre (RMC), Chennai, told the Deccan Chronicle.

“We were able to support the photos of tornado with the pictures recorded in the DWR. It was possible only because of the continuous monitoring of the weather using the Doppler Weather Radar that detects rain clouds and squally winds perfectly up to 25 km” said Dr Y.E.A.Raj, Deputy Director General of Meteorology, Regional Meteorological Centre, Chennai.

According to S.B.Thampi, director, DWR, Chennai, a strong convictive cloud passed through that area on September 12, 2013. He added that he found a tornado vortex signature (TVS) on the Doppler Weather Radar on September 12th evening, which helped them to confirm the track and the location of tornadic rotation after he learnt about the uncommon phenomenon.

Dr Y.E.A, Raj too says there was a definite disturbance during the time mentioned on ECR Road. “We not only encountered intense weather, but our officials, who were travelling in a car to Puducherry  felt the vehicle being jolted to the left of the road. It may not have been an intense tornado as the funnel clouding did not extend to the ground, but  it was unmistakably a tornado,” he concludes.
    Eitherway it was one hell of event which we Chennaites may never hear till their lifetime. Cheers to Robert Gagarin who had the passion to take snap of the once in a life time event.

    1 comment:

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