Nepal experienced strongest windstorms: Meteorologist
By Purushottam P. Khatri
Kathmandu, Apr. 2: Wind storms that lashed Bara and Para districts in the central Terai Sunday night were due to the development of funnel cloud, a cone-shaped cloud, of condensed water associated with a rotating column of wind.
“The funnel cloud got a chance to induce when it got support from various local phenomena or low atmospheric pressures created locally in the various parts of the country since Saturday night,” senior meteorologist Barun Poudel told The Rising Nepal. “
This is one of the strongest wind storms developed so far in Nepal with a speed of 90 kilometres per hour, Poudel said.
Funnel cloud is usually considered as a small part of a cumulonimbus or towering cumulus cloud which doesn’t reach the ground or a water surface most often, but when it touches the ground it turns into a tornado, Poudel said.
He also said that the funnel clouds are formed most frequently in association with supercell thunderstorms.
“Separate cells of thunderstorms developed in the regions, mainly in Pokhara region, gradually moved to Chitwan, Dhading, Makwanpur, and reached Bara and also Biratnagar and exited from eastern Nepal,” Poudel said.
Sporadic separated cells of thunderstorms developed in different places of the country due to a westerly wind accumulated at one place and its extreme impact was seen when it reached the particular regions of Bara district, he said.
“Upper wind developed up to 850 milibar of Nepal’s sky, and this has also led to the funnel cloud situation and low atmospheric pressure in the middle of the sky,” he said.
“This might be the first in history of Nepal that such a strong wind storm took lives of a large number of people causing huge loss to property in the central-Terai,” Poudel said.
The impact of funnel cloud usually has less diametre of coverage of its impact, and even two-three minutes would be enough to cause a huge destruction, he said.
Meanwhile, another senior meteorologist Min Kumar Aryal said that even in the record of Simara-based airport station of meteorologist as of 6:30 pm on Sunday, there was no such specific symptom of any such wind storm but it happened very abruptly.
“Though, we had noticed some separated cells of thunderstorms being developed in several regions of the country from Saturday night, this situation, however, developed all of a sudden when all the separate cells accumulated at one place to create this situation in Bara and Parsa districts,” Aryal said.
“It will be very difficult for us (Meteorological Forecasting Division) to pinpoint the exact location of such disaster when we have a difficult terrain and topography in the country and lack modern equipment like weather radar network and ensemble numerical model which can predict any type of wind storm within a very short time,” Aryal said.
“Additionally, we too have lack of skilled manpower that can predict weather warning and nowcasting,” Aryal said. One of the interesting parts of funnel cloud is that its impact doesn’t go everywhere and remains in one particular place or location, covering a small diametre of space, he added.