Kolkata, May 26 : Just a few hours before the landfall of 'Yass a 'miniature tornedo created havoc in parts of Hooghly and North 24 Parganas on Tuesday evening. Though the weather department said that these kinds of tornadoes are common ahead of a major cyclone but also admitted that it is very unlikely at a place which is nearly 210 kilometres away from the landfall. According to district administrative officials, a tornado that stayed hardly for two minutes was first observed at Bandel in Hooghly district and then it crossed Hooghly river and entered Halisahar in North 24 Parganas. Though none was killed or injured by the tornado but it grounded at least 47 buildings that came in the way. Chief Minister Mamata Banerjee admitted the natural phenomenon and said, "Today, we have witnessed a couple of mini tornados at Bandel (Hooghly) and in Halisahar (North 24 Parganas). More than 40 houses were damaged. In another incident two people were killed in Pandua due to lightning. We are getting information that a few people were also injured". When asked about the incident, Regional Director (Eastern Region) of Indian Meteorological Department Sanjob Bandopadhyay said, "Mesocyclone which is commonly termed as mini-tornado is natural ahead of a severe cyclone. It is not a full tornado that looks like elephant tusk but it is much smaller in form and it lasts for a few months. But this natural phenomenon is very uncommon at a place which is more than 200 kilometres from the place of the landfall". "This happens because of the vertical wind share of a storm where the air in the upper portion of the storm is very high and the air in the lower portion is very low. This difference of speed between two layers of air creates this kind of tornado. So far as this tornado is concerned, it was very weak and lasted for only a few minutes only. If it would last for some more minutes, the devastation would have much more," Bandopadhyay added. Meanwhile, Bandopadhyay said that the impact of the storm would not be much in Kolkata and its adjoining areas. The wind speed would be around 65 km/hr to 75 km/hr at the time of the landfall. "There will be light to moderate rainfall in the city". Answering a question Bandopadhyay said, "We cannot compare Ampahn with Yass because Amphan crossed Kolkata and the path of Yaas is nearly 200 kilometres away from the city. Naturally the impact will be much lower than Amphan". Though there has been assurance from the weather department but Kolkata Municipal Corporation is taking no chances. Former mayor and now one of the members of the Board of Administrators Firhad Hakim who is presently under 'House Arrest' in Narada case has conducted several meetings with the officials virtually and instructed them. The KMC is keeping all its 76 pumping stations and 392 pumps active so that they can pump the water out if there is any kind of water-logging in the city. KMC workers and engineers have been asked to stay at several storm centres created by the corporation so that they respond to any kind of call immediately. /IANS