Local hikers watch glacier fall

Two local hikers saw a big chunk of glacier break away and fall into a lake on Broken Top earlier this month.

Norman Frater of Tumalo and Randy King of Sisters had just finished eating lunch near a nameless 10-acre lake at about 7,800 feet. They turned to leave when they heard a thunderous boom. They whirled around to see a knife-cut edge of ice where an estimate 300-foot section of glacier had slumped into the water.

"The icefall caused a linear 'tidal wave' to traverse the lake, perhaps 4-5 feet high, which washed up on the opposite lake shore, innundating the rocks on which we had just finished eating our lunch," Frater said.

According to Forest Service hydrologist Larry Chitwood, calving glaciers are not very common in Central Oregon - but he's pretty sure that's exactly what the hikers saw.

"It's not too common," Chitwood said, "but on the other hand it is in the context of 13 lakes that formed in a little ice age."

That "little ice age" wasn't so very long ago - it ended in the 1920s and '30s, when the glaciers retreated and left behind basins filled with water.

Events like that witnessed by Frater and King have happened before - sometimes making trouble for the civilization that thrives downslope.

In 1966, the same lake flooded out; water rushed down Soda Creek, hit Sparks Lake and ultimately flooded the Cascade Lakes Highway, covering it with mud, debris and timber to a depth of two or three feet.

Chitwood thinks the '66 flood was probably caused by a glacier calving and causing the lake to surge, pushing muddy water through its outwash stream.

This month's event was a smaller-scale version of the same phenomenon, Chitwood believes.

"A little bigger chunk of ice could have caused another big flood," he said.

However, the chances of flooding from the glacial lakes - including Carver Lake, which perches above Sisters, - seem to be lower than previously believed.

Part of the reason is that there is simply less ice in the glaciers to fall into the lakes.

"The glaciers all across the Three Sisters are in retreat right now," Chitwood said.

He notes that the glaciers are much smaller now than when he first hiked these mountains in the 1970s.

The reasons for the retreat are not completely apparent though drought and climate change may play a role.

Author Bio

Jim Cornelius, Editor in Chief

Jim Cornelius is editor in chief of The Nugget and author of “Warriors of the Wildlands: True Tales of the Frontier Partisans.” A history buff, he explores frontier history across three centuries and several continents on his podcast, The Frontier Partisans. For more information visit www.frontierpartisans.com.

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