LOST LAKE — Yellowstone National Park has Old Faithful.
Arizona has the Grand Canyon.
Linn County has Lost Lake, an 85-acre body of water near the Santiam Pass that has a 6-foot hole in its bottom and virtually disappears every summer.
Lost Lake is about 75 miles east of Albany on Highway 20.
The phenomenon has repeated itself for centuries, according to Jude McHugh, spokeswoman for the Willamette National Forest.
“This area has seen repeated volcanic eruptions that have occurred over the last 12,000 years,” he said. “There are layers of interbedded ash, lava and glacial gravels.”
Originally, it was believed the hole was the entrance of an old lava tube, but Forest Service geologists now say it is mostly caused by fractures in the rock.
McHugh said the hole feeds groundwater that eventually flows into Clear Lake and eventually into the McKenzie River.
“Scientists tracked radioisotopes in the water that showed it might take three to seven years for water to travel from Lost Lake to Clear Lake,” he said.
Lost Lake begins to fill in the late fall, when the amount of rain coming in starts exceeding the ability of the holes to drain off the water and continues to fill all winter long in a series of rain or snowstorms, McHugh explained.
“As the rainy season peters out, the 9-foot-deep lake loses its water source, and water disappears down the hole,” he said. “The lake's fill/drain cycle repeats annually.”
Lost Lake isn’t the only high-mountain lake with a drain hole. Nearby Fish lake has one, too, McHugh said.
Unfortunately, over the years, some people have tried to fill up the hole, McHugh said. U.S. Forest Service staff have found car parts — including engines — in the hole.
“It’s not safe, and modifying natural features is poor outdoor ethics,” McHugh said.
And, she adds, if the holes were plugged, with several small streams feeding the shallow lake, it could cause water to overflow onto Highway 20.
McHugh also asked that persons interested in viewing the hole draining, “tread lightly. There are frogs, snakes and other creatures who make their home there and trampling them would be unfortunate.”
Native Americans originally called the lake “Kwoneksamach” or “unknown,” but Europeans later renamed it “Lost Lake” in the 1870s.
The lake is home to eastern brook trout and rainbow trout. Angling is permitted until September 1 because as the water level decreases, fish tend to group up. No motor boats are allowed.
The Forest Service operates a rustic campground that includes picnic tables and toilets on the west shore of the lake. It operates from June through November. Single campsites are $8 per night.
According to the Atlas of Oregon Lakes, Lost Lake is one of 14 “Lost Lakes” in Oregon, including another one in the Mount Hood National Forest.