Sometimes water that falls in these depression hollows during freak storms collects to form pools in the midst of deserts providing an essential source of water for local ecosystems, animals and humans and their activities.
If an area is eroded down to the water table, further deflation is prevented unless the water table is also lowered by evaporation.
A diagram showing the formation of deflation hollows.
Some oases in the Sahara were formed in this manner and may be below sea level.
Dunes are made from sand that is deposited at the leeward side of the wind.
Some deflation hollows may be formed in part due to the presence of faults within the rocks which are exploited and widened by weathering and the regolith removed by wind erosion.