Visibility reduces to 100 m, traffic hit. Such weather condition not unusual in February, says Met department

Chennaiites woke up to a thick blanket of fog that lasted for over five hours on Monday morning, much to their astonishment.

Due to poor visibility, several incoming flights were diverted while departures were delayed by four hours, leading to over 3,000 passengers being stranded at the airport.

Dense fog persisted between 4.30 a.m. and 9.30 a.m. Visibility was below 100 m during early-morning hours and improved to only 200 m around 8.30 a.m. Meteorological Department officials said it was not unusual for such thick fog to descend on the city during the month of February. They said the month normally has five to six foggy days.

As visibility was low, traffic slowed down on arterial roads. Many motorists plied with headlights turned on. Parents taking their children to school suffered as they could not avoid travelling on the foggy morning. “My son had to submit a project in his school. It is the first day of the week and we did not want him to take leave. I drove very slowly to the school, which is four km away,” said S. Shanthi, a resident of Anna Nagar.

Several office-goers left for work at least an hour late. “I had tough time riding through the fog and could not see even a few feet away. It was cold and visibility was poor in localities with dense vegetation,” said R. Narayanan, a resident of Karapakkam.

Four flights cancelled

Dense fog in areas surrounding Chennai airport delayed arrival and departure of flights. A press release from the Airport Director said “unusual fog” prevailed from 4.15 a.m., preventing flights from either landing or taking off. The first flight took off from the airport only around 9.30 a.m.

The departures of nearly 30 flights, both in domestic and international sectors, were delayed by more than four hours. In both the sectors, four flights were cancelled. A total of 15 flights, including nine international flights and the remaining in the domestic sector, that were to land at Chennai were diverted to other destinations. While a dozen flights were diverted to the Bangalore international airport, one each was diverted to Tirupati, Kochi and Colombo, according to airport sources.

“High humidity level and lower atmospheric stability result in foggy conditions. On Monday the humidity level rose up to 98 per cent,” explained Y.E.A. Raj, Deputy Director General of Meteorology, Regional Meteorological Centre.

R. Suresh, Director (in-charge), Aerodrome Meteorological Services, said a visibility level of a minimum of 500 m was required for arrival or departure of flights in airport.

On Monday, it was hardly 100 m. There was no wind and it took time for the fog to dissipate.

The incoming solar radiation, which normally hits the surface by 5.30 a.m., came in only around 8.30 a.m. on Monday. He said that there are 29 foggy days in a year spanning between January and March.

Chennai experienced a similar thick fog in February three years ago, he added.