Visions of 2012 in dark January

5am Kolkata: thunder, lightning and torrents of rain. 9.20am Bombay: sunshine and traffic. From disaster movie to real life in 4 hours. Surreal.

' Deepanjana Pal's tweet on Monday morning

Calcutta, pounded by rain at night and waking up to a dark Monday morning, could not be faulted for conjuring up visions of 2012, Hollywood's apocalypse film triggered by climate change.

The city received 71.7mm of rain in the past 24 hours till 8.30pm on Monday, against the January mean of 11.7mm. This took the total rainfall since January 1 to more than 96mm.

Only once in recorded Met history did the city receive more showers on a January day. "On January 8, 1967, the city had recorded 99mm of rainfall," said G.C. Debnath, the director of India Meteorological Department, Calcutta.

The spell is not likely to end soon, with the weatherman warning of more rain or thundershowers in the city and its surrounding areas in the next 48 hours.

The unusual occurrence is the result of a confluence of two atmospheric systems, one of which has travelled from as far as the Mediterranean region while other has originated over the Bay of Bengal.

"A cyclonic circulation over Jharkhand and an anti-cyclonic formation over the Bay are working in unison to draw moisture from the sea, leading to the formation of convective clouds and thunderstorm activity. This is a rare event for January," said Debnath.

The formation over Jharkhand has resulted from a western disturbance, which originates near the Mediterranean Sea and moves east across West Asia to India, driving cold air across the northern Indian plains.

Is the "rare phenomenon" indicative of any far-reaching change in the weather system?

Tough to tell. While researchers studying climate change have documented an increase in extreme rainfall events in recent decades and attributed it to global warming, weather scientists say they are not sure whether this heavy rainfall in Calcutta can be linked to any increase in extreme events.

"Climate change needs to be studied through long-term observations," said Madhavan Rajeevan, a senior scientist at the National Centre for Atmospheric Sciences, Tirupati, Andhra Pradesh.

Whatever be the reason for the unseasonal showers, several Calcuttans were reminded of the 2009 Hollywood blockbuster that portrayed the end of the world in 2012 following large-scale flooding caused by earthquakes.

Some saw in the rain a pattern marking an ominous start to the year ' "Rain in Kolkata, Volcano in Sicily... Earthquake in Santa Cruz Island! : Welcome 2012!:)', tweeted Souvik Dhar on Monday.

Calcuttans in several pockets, including Ballygunge Place, Amherst Street, Surya Sen Street, Dhakuria, Ekbalpore, Behala and Tiljala, waded to work through waterlogged streets.

Birla High School for Boys and Girls and Calcutta Girls', which had exams scheduled for Monday, declared a holiday. Mahadevi Birla Girls' Higher Secondary School saw a half-day. The authorities at Apeejay's Park Street and Salt Lake schools said many students could not reach before 9.30am though classes began at 8am.