Parts of Asia were reeling after torrents of rain unleashed catastrophic floods and landslides last week, killing more than 1,400 people in Indonesia, Sri Lanka, Thailand and Malaysia. The disaster has also laid bare stark economic disparities in the region.

Emergency crews raced to reach survivors as the death toll from last week’s catastrophic floods and landslides surged past 1,300 in Indonesia, Sri Lanka and Thailand – with more than 800 people missin...