The dunes move.

They are not static geological features but dynamic bodies of material in constant slow motion, driven by the prevailing winds of the Tularosa Basin from the southwest.

The dunes advance across the basin floor at rates that have been measured and tracked over decades, burying terrain ahead of them and exposing terrain behind them as they pass.

In the wake of the advancing dunes, deflation surfaces — areas where the wind has removed loose material and exposed underlying, more consolidated layers — develop and evolve over time.

It is on these deflation surfaces, in the areas where the dunes have moved and the lakebed sediments beneath them have been exposed, that the footprint surfaces are found.

The same process that created the dunes — the evaporation of Lake Otero and the wind transport of the resulting gypsum — also contributed to the conditions that preserved the footprints, and it is the ongoing movement of the dunes that is slowly re-exposing them.