Over 250 people have died in floods.
By Sreejith Vallikunnu
NASA’s recent animated map that provides satellite-based estimates of rainfall over south-eastern India, shows that on December 1-2, Chennai received more rainfall in 24 hours than it had seen on any day since 1901.
The deluge followed a month of persistent monsoon rains that were already well above normal for Tamil Nadu, NASA’s Earth Observatory said in a blog post.
At least 250 people have died, several hundred more are critically injured, and thousands affected or displaced by the flooding that ensued.
The rainfall data come from the Integrated Multi-Satellite Retrievals for GPM (IMERG), a product of the Global Precipitation Measurement mission, NASA said.
According to Hal Pierce, a scientist on the GPM team at NASA’s Goddard Space Flight Center, the highest rainfall totals exceeded 500 mm (20 inches) in an area just off the south-eastern coast.
The blog post added that “meteorologists in India and abroad attributed 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 north-easterly 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.”
It also said, “In 2015, this pattern was amplified by record-warm seas and by the long-distance effects of El Niño. 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.”
A week after severe flooding Chennai is reaching the post-impact phase of the disaster.