Dead cottonwoods, long buried under the still waters of Lake Powell, have reemerged as "ghost forests."(Alex Hager / KUNC)

Lake Powell is the nation’s second-largest reservoir but climate change and overuse have dropped the water level to a record low, leaving the water supply uncertain for tens of millions in the southwest.

KUNC’s Luke Runyon took a boat trip to report on the changing landscape for the Mountain West News Bureau as part of his ongoing coverage of the Colorado river, produced by KUNC and supported by the Walton Family Foundation.

KUNC reporter Alex Hager took even more amazing pictures from his trip.