22 Aug 2018: What caused the Kerala floods? NASA reveals the reason

22 Aug 2018: What caused the Kerala floods? NASA reveals the reason

NASA has released a video using satellite data that provides an estimate of rainfall and shows the spread of the resulting severe flooding in Kerala.

The summer monsoon is a regular feature this time of year in India that can bring heavy rains to the region. However, periodically, low-pressure areas can form within the general monsoon trough and bring even more rain.

Here's more.

Fact: Center has declared the flooding calamity of 'severe nature'

Kerala is facing its worst floods in nearly a century that left at least 231 people dead and forced thousands of people out of their homes. The Center has declared this calamity of 'severe nature'.

Western Ghats: Western Ghats is another contributing factor towards the heavy rains

Another contributing factor to the heavy rains along the southwest coast of India is the Western Ghats, the mountain range which runs parallel to India's West Coast.

As a result, the Western Ghats is well positioned to enhance rainfall along the West Coast as it intercepts the moisture-laden air being drawn in off the warm waters as part of the southwest monsoon circulation.

GPM: This is how the NASA estimated the rainfall patterns

The Integrated Multi-satellite Retrievals for GPM (IMERG) is used to estimate precipitation from a combination of passive microwave sensors, including microwave sensor and infrared data.

GPM is the Global Precipitation Measurement mission core satellite. GPM is a joint mission between NASA and the Japan Aerospace Agency, JAXA.

Rainfall accumulations from August 13 to 20, 2018 showed two bands of heavy rain across India.

First band: First band is associated with the general monsoon circulation

The first band appeared much broader and extends across the northern part of the peninsula with weekly rainfall totals ranging from over 5 inches towards the western half of the peninsula to as much as 14 inches over parts of the eastern half towards the Bay of Bengal.

The first band is associated with the general monsoon circulation.

Second band: Second band is aligned closely with the southwest coast

The second band appeared more concentrated and intense and is closely aligned with the southwest coast and the Western Ghats where onshore flow was enhanced by an area of low pressure embedded within the general monsoon.

Weekly rainfall totals in this band are generally over 10 inches with embedded areas exceeding 16 inches. The maximum estimated value from IMERG in this band was 18.5-inches.