Saturday, October 8, 2011

Look, Ma! - no Cyclones!


Cyclones, depressions and low pressure areas which form in the Bay of Bengal usually cause periods of intense, heavy downpours which result in landslides in the Darjeeling-Sikkim Himalayas. As such STH has been plotting/tracking these phenomena on the Internet for some time now (see 1, 2, 3, 4 & so on) .
A record of the cyclones which brewed up in the Bay of Bengal in 2010 (with date and surface wind) is placed above and what is absolutely amazing is that in 2011, we have not had a single cyclone forming in the Bay till date and the number of depressions which have formed is also below normal.
All this when the Philippines has been hit by 3 major back-to-back typhoons within the last one week!
But then our cyclone season lasts upto December ....
For those interest please find below the Classification of bad weather phenomenon as per the IMetD :-

Classifications of cyclonic disturbances for the north Indian Ocean region are given below:-

Weather system                               Maximum wind speed
1. Low pressure area…………………..Wind speed less than 17 kt (31 km/h)
2. Depression………………………….. Wind speed between 17 and 27 kt (31 and 51 km/h)
3. Deep Depression…………………….Wind speed between 28 and 33 kt (52 and 61 km/h)
4. Cyclonic storm ……………………….Wind speed between 34 and 47 kt (62 and 88 km/h)
5. Severe cyclonic storm……………… Wind speed between 48 and 63 kt (89 and 118 km/h)
6. Very severe cyclonic storm…………Wind speed between 64 and 119 kt (119 and 221 km/h)
7. Super cyclonic storm ………………..Wind speed 120 kt (222 km/h) and above

Praful Rao

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