Mapping Inundation extent for Colombo District in Western Province (Sri Lanka) using ALOS 2 PALSAR 2 Satellite Data (23 May 2018)
Heavy rainfall occurred on 20th and 21st May 2018 which has resulted in flooding forcing evacuation of people in low-lying areas where four Major rivers have reached flood levels, while 6 districts are on "red alert" for possible landslides. About 153,500 people have been affected by the floods. The death toll in Sri Lanka's monsoon rains has climbed to 12 as 24th May 2018 (DMC reports).
The initial satellite observations from ALOS-2 PALSAR-2 (23 May 2018) showed vast areas of standing flood waters along the North Western, Western and Southern Provinces. Initial estimates from satellite images indicate that Puttalam (96.1 sq.km), Kurunagala (198.6.sq.km), Gampaha (82.46 sq.km) Galle (25.5 sq.km, Kaluthara (22.1 sq.km), Rathnapura (10.4 km.sq), Colombo (4.2 sq.km). Most of the district flood is reducing but rivers are still under minor flood level.
The satellite image from ALOS-2 PALSAR-2 taken on 23 May2018 showing considerable inundation for Galle and reference to dark with deep water and dark grey color in the agriculture fields with water.