Bengaluru rain: What’s behind Garden City’s wettest November in six years?

The Indian Meteorological Department’s (IMD) Bengaluru observatory has recorded 115.8 mm rainfall between November 1 and November 14, twice the average, making it the city’s wettest November in six years. Bengaluru recorded 71 mm rainfall last November.

Low-pressure areas over the Bay of Bengal and the Arabian Sea and cyclonic circulations have contributed to this year’s downpour.

November rain in Bengaluru
The northeast monsoon has gathered strength from a network of cyclonic circulations and a low-pressure area over the Arabian Sea and the Bay of Bengal. The low-pressure area is likely to move towards the west-northwest and become more marked by Thursday.

The IMD said a trough was also running from the cyclonic circulation associated with the low-pressure area over the east-central Arabian sea off the coast of Karnataka to the low-pressure area over southeast Bay of Bengal.

The weather agency has forecast light-to-moderate rainfall at most places. It has also predicted heavy rainfall at isolated places of coastal & south interior Karnataka, Puducherry & Karaikal, Tamil Nadu, and coastal Andhra Pradesh over the next five days and Rayalaseema over the next three days.

The IMD’s latest satellite imagery suggested that light-to-moderate rainfall with isolated spells of thunderstorm and lightning is likely over south peninsular India — Kerala, Tamil Nadu, Andhra Pradesh, coastal and south interior Karnataka, and south Goa.

A cyclonic depression over the Bay of Bengal caused heavy rainfall in parts of Bengaluru, the Met department had said.

Excessive rainfall in Bengaluru in November
In November 2015, Bengaluru received 296.4 mm rainfall. The city recorded 143.7 mm rain in November 2013, 125.0 mm in 2012, and 49.9 mm in 2011.

Chilly weather in Bengaluru
Bengaluru is forecast to receive rain till Thursday, while the evenings will be colder. IMD Bengaluru Director-in-Charge Dr Geeta Agnihotri said the sky would remain cloudy due to the current weather system.

It will take for this weather system to dissipate. As a result, in the absence of sunshine, Bengaluru will experience cold weather, Dr Agnihotri told The Indian Express.

IMD scientists added that extreme weather patterns, including the distribution of rainfall, were becoming more frequent. Some areas in Bengaluru receive very heavy rain while some others witness very light-to-moderate rainfall in a single day, a weather scientist added.

Flood prevention
The heavy downpour led to Karnataka Chief Minister Basavaraj Bommai ordering the Bruhat Bengaluru Mahanagara Palike to submit a report on its short- and long-term plans to prevent flooding in the city.

He also directed civic officials to identify stretches with weak stormwater drain retention walls. Experts said of the city’s 842 km stormwater drain network, retaining walls had been constructed only for 389 km, leading to flooding.

Bommai has already announced that the civic body’s 15-member rescue teams would be increased to teams of 30 by pooling in manpower from the civil defence and the home guard. Bengaluru currently has 64 rescue teams.