One of the glacial rivers feeding a large lake straddling the Yukon-British Columbia border has dried up, hikers say, turning a normally fast-running watercourse into a muddy field strewn with house-sized icebergs.

"We were able to walk right into the river bed and stand among the 60-foot icebergs that are grounded now," said Diana Thayer of Atlin, B.C., who came across the phenomenon while hiking near the Llewellyn Glacier along the Sloko Inlet trail in late August.

"It just seemed the plug had been pulled on a bathtub."

An aerial view of the now-muddy expanse where Sloko Inlet used to spill glacial water into Atlin Lake, B.C. (Submitted by Diana Thayer)

Frigid meltwater from the glacier, part of the Juneau Icefield, normally flows into Atlin Lake at several points, which include Sloko Inlet and Llewellyn Inlet. Now it appears that the Sloko Inlet source has run dry.

Thayer said that a small lake at the foot of the glacier has already "dropped about 50 feet and perhaps is still draining."

A neighbour of Thayer's, John Lyons, visited the site the day after she returned and described what he saw.

"The photographs were spectacular ... You see where the 'bergs had been dragged along the bottom and you could see the drag marks in the mud from all the various icebergs," he said.

"The maps will have to be redrawn a bit because there's no more river there."

Lyons said it looked as though an ice bridge had dammed the waterway to Sloko Inlet, forcing the meltwater that had previously been split between two paths to flow entirely towards Llewellyn Inlet.

Atlin residents weren't the only ones caught off guard by the shift in glacial melt flows.

Icefield researchers working in the area this summer found normally dry walking trails to the Llewellyn Inlet flooded with chest-deep water.