Next time you hear a Seattleite say, “The mountain is out,” take a closer look. Does Tahoma look a little smaller lately?
OK, you can’t actually tell with a glance but in fact Mount Rainier—also known by its Indigenous name Tahoma—is nearly 22 feet shorter. A recent measurement of its peak found that the Mount Rainier summit has shrunk due to climate change.
The discovery was made in September 2024 by Eric Gilbertson, an engineering professor at Seattle University and an experienced mountaineer who has summited mountains in over 100 countries.
He found that Mount Rainier’s summit, called Columbia Crest, has melted almost 22 feet since 1998. The new summit is about 500 feet away (horizontally). Since it is on rock, it is unlikely to change again.
U.S. Geological Survey took the last recorded measurement in 1998. Gilbertson attempted this to take this measurement in 2023 but couldn’t reach the summit due to wide crevasses, which he said was unprecedented for him.
How was the new summit measured?
Gilbertson received a grant from American Alpine Club to measure mountains in Washington State and see how they were being affected by climate change. He uses modern technology and satellite data to determine measurements that are accurate to within one inch.
Next, Gilbertson plans to measure other peaks in Washington including Mount St. Helens, an active volcano that could be shrinking as much as four inches annually—possibly due to erosion in this case.
How will this impact climbers trying to summit Mount Rainier?
GearJunkie spoke to Zeb Blais, the owner of Washington-based Blackbird Mountain Guides. Blais said that it depends on the route but that the new location could possibly add a mere 10 minutes to the time needed to summit Mount Rainier.
However, the new summit is indicative of a larger change that is making the mountain more dangerous to climb. As glaciers on Rainier melt due to climate change, guides are forced to take much longer routes to avoid them.
“Climbing the mountain has gotten more complicated,” Blais said. “[The guides are] taking extreme measures to get around obstacles that the glaciers now present.”
Are other mountains shrinking too?
Besides demonstrating a measurable effect of climate change on Mount Rainier and other mountains that have ice caps on their peaks, Gilbertson’s discovery has another interesting takeaway. It throws into question the true summit of other mountains in the world.
Gilbertson told GearJunkie that “most mountains in the world” haven’t been measured with the level of accuracy that the new technology affords. “I think there’s a good chance that the elevations are not quite what we think.”