How flat are playa surfaces compared with other landforms?

Playas are among the flattest landforms on Earth, characterized by slopes that are generally less than 0.2 metres per kilometre. This near-perfect flatness is primarily developed and maintained through the process of inundation, where periodic flooding allows water to spread evenly across the basin floor, depositing fine-grained sediments and salts.1

While they are defined by this extreme levelness, the surface texture can vary significantly based on local conditions:

• Smooth Surfaces: Regular flooding of evaporative layers can create exceptionally smooth surfaces, such as those found at the Bonneville Salt Flats.2
• Rugged Crusts: In some areas, thick salt deposits can form rugged, uneven crusts, such as the salt karst topography found at the Devil’s Golf Course in Death Valley.2
• Desiccation Features: Clay-rich surfaces may develop polygonal networks of cracks or giant desiccation polygons due to sediment contraction during prolonged droughts.2

In contrast to these flat central basins, other landforms in arid regions often feature more pronounced relief, such as the mountainous deserts of North America or the downwind dunes associated with wind deflation basins.31