Historic rainfall floods southeast India

India’s southeastern state of Tamil has seen a month of the heaviest rains in over a century, beginning November 12, 2015. In the massive flooding that has ensued, at least 250 people have died, several hundred have been critically injured, and thousands have been displaced. On December 1–2, 2015, the state capital city of Chennai received more rainfall in 24 hours than it had seen on any day since 1901.

In Chennai, which has a population of about 4.5 million people, the flooding has closed factories, turned of power, shut down the airpott and forced thousands of people out of their homes, reports the Huffington Post. In some parts of the state, people have been forced to walk through neck-deep water.

According to a NASA report, meteorologists attribute the rains to a super-charged northeast monsoon. In the winter, prevailing winds blow from northeast to southwest across the country, which tends to have a drying effect in most places, particularly inland. But those northeasterly winds also blow over the warm waters of the Bay of Bengal, where they evaporate a great deal of moisture from the sea and dump it over southern and eastern India. Coastal eastern India receives 50 to 60 percent of its yearly rainfall during this winter monsoon.

In 2015, this pattern was amplified by record-warm seas and by the long-distance effects of El Niño, says NASA. The city of Chennai recorded 1218.6 millimeters (47.98 inches) of rain in November 2015, according to Weather Underground blogger Bob Henson. India’s meteorological department noted that rainfall was 50 to 90 percent above normal in the eastern states. Then 345 millimeters (13.58 inches) more fell on Chennai in the December 1–2 storm, which was fueled by a low-pressure system offshore.

Enjoying EarthSky? Sign up for our free daily newsletter today!

Bottom line: India’s southeastern state of Tamil has seen a month of the heaviest rains in over a century, beginning November 12, 2015. In the massive flooding that has ensued, at least 250 people have died, several hundred have been critically injured, and thousands have been displaced. On December 1–2, 2015, the state capital city of Chennai received more rainfall in 24 hours than it had seen on any day since 1901.

Read more from NASA’s Earth Observatory