Floods are a type of natural disaster that occur when a region is flooded with water. The causes of flooding are either a dam failure, heavy rain, tsunamis or risen lakes/rivers. Floods cause severe damage to buildings and places, leaving a ton of wreck when the floods subside.
After a massive solar flare caused the Earth's core to heat up, the crust became unstable and caused the world's ending to occur in 2012. The tectonic plates destabilized, which caused massive floods to occur around the world, alongside gigantic megatsunamis at the height of 1500 meters (formed by the magnitude of the corresponding quakes), flooding the entire planet with water. The massive flooding caused severe damage to the Earth's continents, wiping out global communication, electricity, and radio relays.