Deadly squalls and dust storms have thrown life out of gear in northwestern India over the past 45 days.
As per data accessed from the Delhi Regional Meteorological Centre (India Meteorological Department), the city has already witnessed five squalls and gusty wind episodes within the first 16 days of May. The monthly average for such episodes in the entire month of May is eight.
In 2017, four episodes of squalls along with dust storms and thunderstorms were reported throughout the month. In 2016, this number was eight — of which only three were reported in the first half of the month. This trend, where more squalls are reported in the second half of May, were seen in 2011 and 2012. However, 2013 was an outlier as no squalls were reported the whole month.
As per IMD officials, for an incident to be recorded as a squall, the wind speed has to pick up abruptly and strong winds have to sustain for at least a minute. The minimum wind speed for a squall is usually around 40 km/hour.
According to IMD officials, the reason that more squalls are recorded in the second half of May is that the maximum
temperature is in the range of 40-43 degrees Celsius during this period.
“A squall usually develops when there is a western disturbance or interaction between two different wind systems at a time that the surface temperature is high. The higher the temperature, the stronger the squall and the wind speed,” said a senior Met official.
According to Met records, the strongest squall in Delhi in recent times was reported on May 30, 2014, when the wind speed breached the 114 km/hour mark. Twelve people died across Delhi-NCR after trees and hoardings fell on them.
This year, the strongest wind speed during a squall was reported on May 13 at 109 km/hour.