Devil Mountain Maar deposited a tephra called the Devil Mountain Lake tephra over an area of . It reached thickness of more than over an area of , burying soil and vegetation and falling into lakes. The soil found underneath the Devil Mountain Maar tephra is known as Kitluk paleosoil. Plant remains found buried underneath the tephra are well preserved and have been used to infer climatic and biotic conditions during the last glacial maximum in the region; vegetation at that time was apparently different from today and there was no widespread ice cover. The tephra is used as a tephrostratigraphic marker for the late Pleistocene. The eruption of the Killeak Maars also produced tephra deposits, which are also found in lakes and have similar compositions to the tephra of the Devil Mountain Maar. Their deposition disrupted local wetlands and altered the topography.