The Kerala State Disaster Management Authority (KSDMA) is embarking on a detailed study of the gustnado, the short-lived but often destructive whirlwinds, that is being reported in different parts of the State. The idea is to see whether these extremely localised events can be forecast.
The decision comes at a time when such ‘freak’ weather phenomena have been noticed during the current southwest monsoon season, most recently from Chalakkudy and Kasaragod.
The KSDMA has assigned one of its meteorologists with the task of examining the gustnado events reported in the State in detail, says KSDMA member secretary Sekhar Kuriakose.
“We are exploring the possibility of forecasting them. These events are very localised. We have collected the data on them and intend to examine whether any indications to them were there in the 24-hour weather forecasts,” he said.
2016 study
The KSDMA came out with its first research report on a gustnado event in the State in 2016 following a study of an event reported in Poruvazhi village in Kollam district. The report noted that a similar event, which also left a trail of destruction, was reported in 2014 near Thrikkunnapuzha in Alappuzha district
The KSDMA report noted that gustnado is are short-lived, lasting from a few seconds to a few minutes at the most, but its wind speeds can range anywhere between 80 kmph and 180 kmph. Unlike cyclones, the rotating column of air in a gustnado does not connect with the base of the thundercloud although it is in contact with the ground, the reason for its short life and limited range, according to the report.
Though fleeting, gustnado in Kerala has been known to cause serious damage to houses and crops.
Climate change
The 2016 report also pointed out the recurrence of such localised whirlwinds and cloud burst events in Kerala against the backdrop of climate change.
Given such a possibility, the State government, on the recommendation of the KSDMA, notified “Strong wind less than cyclone or cyclone storms which causes damages to life and property” as a State-specific disaster along with lightning and coastal erosion.
On its part, the India Meteorological Department (IMD) does not officially use the term gustnado to describe such weather phenomena, but consider them a result of thunderstorm scenarios or squall lines, an IMD official says.
