Scientists have been left baffled by a record spike in earthquakes near Washington's Mount Adams volcano that has ... could generate far-traveled lahars,' USGS officials wrote.

Mount Adams ... lahars, or muddy flows of rock, ash and ice that 'surge downstream like rapidly flowing concrete' and can occur during eruptive or non-eruptive periods, according to the USGS.

Six earthquakes hit the "high threat" volcano in September, according to the United States Geological Survey ... threat to ...