Ant hill flooding.

Just what is/are the physics behind the tunnels in an ant hill that keep them from being flooded during a strong storm.
I have only seen ants give up and “raft” during an actual flood where there is standing water, but have never seen much activity during a generic cloudburst.
Hep me.

Ant nests are built with drainage; water flows through them and out the bottom without affecting the main portion of the nest. A major flood would cause a problem, but a regular rainstorm – even a heavy one – has little effect.

I’ve noticed that on warm, humid summer days (when the weather feels ‘thundery’ and a torrential downpour is often imminent), the ants here often surround the entrances to their nests with little hills of fresh soil, presumably this forms some kind of defence against the influx of water.

Reality Check, water flows out the bottom? The bottom of what, the earth? Cite please.
Hell I can’t even find a good diagram.

In most cases, ant nests are not all that deep, not even extending through the full depth of the topsoil (at least that is the case here) - there is usually plenty of soil between the bottom of an ant nest and the water table for water to drain into.

Mangetout has it – there is room beneath the lowest tunnel of the nest (that’s what I meant by “bottom”) and the water table. The water flows through the “drainage” tunnels and into the soil below.