The frequency and intensity of short-lived micro-scale whirlwinds are on the rise in Kerala, especially during monsoon season, although there are not enough documented records of these localised extreme weather events with the authorities.
However, weather events, also known as gustnadoes, are wreaking havoc across Kerala with close to a dozen such events being reported from various parts of the State over the past three weeks.
In the latest such incident, a whirlwind that struck parts of Thrissur such as Puthukkad, Varandarappilly, Nanthipulam four days ago wreaked widespread havoc.
Speaking to The Hindu, Neetha K. Gopal, India Meteorological Department (IMD) Director, Thiruvananthapuram, said the Thrissur sites were inspected by officials. However, no data were available with the IMD to categorise the event on its intensity.
“On the other hand, a similar incident was reported near Pinarayi in Kannur where an automatic weather station had recently been set up by the IMD. The wind that struck the region had a speed of around 60 kmph. Often, these weather events last a few seconds or one to two minutes. Since the event is highly localised, with the wind system having a width of approximately 20 metres and a 100- to 200-metre length, it is hardly being noticed on the radars of the weather agencies,” said Ms. Gopal.
“We have to go for an in-depth analysis based on the available materials, like video footage, before making a detailed comment on the causes of the spurt in such weather events during monsoon,” she said adding that it was not right to term the wind system as gustnadoes as these winds came under the category of whirlwind with a relatively low intensity compared to tornadoes..
Kerala State Disaster Management Authority (KSDMA) member-secretary Sekhar V. Kuriakose said the agency started to keep track of the incidents in 2014 following such a weather event near Thrikkunnapuzha in Alappuzha district, which left a trail of destruction in the region.
Later, the KSDMA came out with its first research findings on a gustnado in the State in 2016, following a study of another event reported in Poruvazhi village in Kollam. “It is true that the frequency of these weather events has seen a sharp rise in recent years, and the agency has been providing financial assistance to the affected people,” he said.
Experts said the rise in temperature was leading to an increase in the number of such weather events. The whirlwinds seemed to be local, and their causes were also either regional or local.
One of the main reasons for the development of localised whirlwinds was the climatic changes within the region, especially the decrease in monsoon rainfall and rise in temperature. The increased temperature in the absence of rain at one place may produce gustiness while raining, said the experts.
