On Day 20/21 of the Monsoon Season, my base suddenly flooded instantly regardless of the crafted turf.
From what I could tell, in the space of a second, a puddle appeared and grew to the maximum size, flooding the entire base. Please see the attached image.
1. Monsoon Season (Near the end) 2. Crafted Turf filling entire screen 3. I was running into my base when it happened