In awe of a massive thermokarst thaw slump freighting tons of silt and mud into the Noatak River, Noatak National Preserve, Alaska ... Former Denali park ranger Jon Waterman has been visiting ...

Marinell Chandler is back at work with the National Park Service in Alaska after being laid off ... Yet the emotional roller coaster the 33-year-old park ranger has been riding for two months ...