Thick mist has put motorists at risk on arterial stretches like Chennai - Bengaluru Highway (NH 48) and Ranipet - Krishnagiri High Road (SH 24) in Vellore, Ranipet, Tirupattur, and Tiruvannamalai districts due to low visibility of vehicles.
Meteorologists at Vellore Observatory of India Meteorological Department (IMD) said that early arrival of thick mist in inland areas like Vellore, Ranipet, Tiruvannamalai, and Tirupattur districts was due to a lack of sea breeze that reduces occurrence of early mist or haze during monsoon.
Early mist and haze, meteorologists said, also indicates long and cooler nights and less daylight. “Coastal areas like Chennai have the advantage of sea breeze that reduces harsh cold weather during night. The intensity of cold weather will be felt much higher in January - February in inland areas like Vellore and surrounding districts,” N.A. Nehru Raj, meteorologist ‘A’, Vellore Observatory (IMD), told The Hindu.
Mist forms due to temperatures dropping below dew point, which is the measure of moisture and excess humidity. Areas like Gudiyatham, Katpadi, Walajah, Arcot, Vaniyambadi, Tirupattur, Arani, Arakkonam, Tiruvannamalai town, Cheyyar, and Vandavasi have been experiencing thick mist. Traffic on arterial stretches like the Chennai - Bengaluru Highway (NH 44) and Cuddalore - Chittoor Highway was also affected due to poor visibility. “We have to depend on headlights of vehicles to get better visibility of vehicles on arterial stretches. Adequate safety measures like blinkers and reflectors should be placed on elevated corridors and bridges,” said B. Vinod, a motorist.
Meteorologists said that mist allows visibility to a distance of only up to 1.5 kms due to thick dust particles. During haze, motorists can view vehicles and objects clearly to a distance of around five km.
Mostly, mist occurs until 9 a.m, followed by haze until 11 a.m in the region. During haze, hot weather gradually increases, providing more sunshine in the afternoon. Fog poses more risk for motorists as visibility of vehicles is possible only up to a distance of less than 500 metres.
Another feature of the change in weather is that inland areas will witness long night hours whereas the daytime will be shorter. It has been recorded that sunset in Vellore and neighbouring areas in the region is around 5.30 p.m since last week, indicating a change in the weather pattern. Prior to this, the sunset in the region was around 6.45 p.m.