Disappearing glaciers of the Oregon Cascades, USA

Anders Carlson, Nicolas Bakken-French, Megan Thayne, Sam Pappas, Daniela Molnar, Dylan H. Rood

The Oregon Cascades had 35 named glaciers on seven volcanos in the 1980s, with 34 of those glaciers remaining by 2000. Here we document the glaciers that fall into the Global Glacier Casualty List categories based on five years of field observations of these 34 glaciers. Five glaciers have disappeared, four have almost disappeared, and eight are critically endangered. Thus, half of the Oregon Cascade named glaciers have disappeared, almost disappeared, or reached critically endangered status in the 21st century. Between 1995 and 2024, six snow telemetry stations recorded May-October warming at ~0.8°C per decade with a 2020-24 mean temperature ~2.3°C warmer than the 1995-99 mean. In contrast, April snowpack showed statistically significant declines at only two of the six stations. Given the significant rise in melt-season temperature and limited evidence for a reduction in snow accumulation, we attribute ongoing glacier disappearance in the Oregon Cascades to the warming climate.