CHENNAI: The record rainfall, unseen in the past two decades, which pounded Puducherry, Villupuram and Cuddalore districts in north Tamil Nadu and Krishnagiri and Dharmapuri districts in the west over the last two days blocked access to several villages and residential colonies, inundated thousands of acres of crops and stranded hundreds of passengers as rail and road traffic was hit.
In 24 hours ending at 8.30 am Monday, Uthangarai in Krishnagiri district received 50cm rainfall, Kedar in Villupuram clocked 42cm, and Harur in Dharmapuri recorded 33cm. Cuddalore and Tiruvannamalai had recorded 16cm each.
Vehicles and roads were submerged in several parts of Villupuram and Cuddalore. Traffic was temporarily stopped on the Chennai-Tiruchy national highway. With water rising on an arterial bridge between Vikravandi and Mundiyampakkam, Southern Railway on Monday suspended operations on the stretch.
Rains to continue in interior TN districts with reduced intensity
According to experts, the intense rainfall was primarily due to the cyclone’s trajectory which brought it close to the northern parts of Tamil Nadu before it weakened gradually into a well-marked low-pressure area.
As cyclone Fengal moved inland, it carried a massive amount of moisture from the Bay of Bengal. Krishnagiri, situated along the cyclone’s path, experienced concentrated rain due to the interaction of the cyclone’s winds with the region’s topography, amplifying precipitation.
This phenomenon is common when cyclones move over land, particularly in areas with hilly terrain, as they cause orographic rainfall (rainfall enhanced by elevation changes).
Officials at the regional meteorological centre said that although Fengal weakened into a depression, it continued to deliver heavy rainfall due to its slow movement and persistence over interior Tamil Nadu. Such extended durations of rain over specific areas often lead to extreme rainfall events like the one in Krishnagiri.
The cyclonic storm crossed north Tamil Nadu and Puducherry coasts on the midnight of November 30, but it remained stationary close to the coast for several hours and moved very slowly into the interior districts hammering Puducherry, Cuddalore, Villupuram, Krishnagiri, Kallakurichi, Dharmapuri and Tiruvannamalai.
“This is a very unique system, which even after landfall, stayed close to the coast drawing moisture from the Bay of Bengal. The ocean was also warm with surface temperature clocking 28-29 degrees against the normal of 25-26. This increases the moisture feed into the weather system, which is why Fengal did not weaken. From being a cyclone, the system took substantial time to weaken into a deep depression, and now a well-marked low-pressure area. This time, lag kept the system alive and convective clouds brought with it record rains,” said Mahesh Palawat, vice president (meteorology and climate change), Skymet.
The rains in the interior districts of Tamil Nadu is expected to continue on Tuesday but with reduced intensity. A Yellow alert (heavy rainfall) was issued for Krishnagiri, Dharmapuri, Salem, Namakkal, Karur, Erode, Nilgiris, Coimbatore, Tiruppur, Dindigul, Theni, Madurai, Tiruchy, Perambalur and Tirupattur districts. The met office said the remnant of the low-pressure area is likely to emerge into the southeast and adjoining east-central Arabian Sea off north Kerala-Karnataka coasts on Tuesday.
Stalin requests Rs 2K cr from centre
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