The US West Has Lost Nearly 400 Glaciers
By Sustainability Awakening • Dr. Ahmad Mahmood
Mid-century map
1,453 glaciers
USGS maps from the 1950s–80s showed 1,453 glaciers across the lower 48 states.
Source: Fountain et al., PNAS 2026
Vanished
398 glaciers are gone
27%
Share of mid-century glaciers that disappeared by about 2015.
Source: PNAS 2026
Ice cover
A third of the area melted
Mid-century562 km²
About 2015367 km²
Source: PNAS 2026
Ice volume
One third lost
Before19.7 km³
Now13.2 km³
89% of what is left sits in Washington’s North Cascades.
Sierra Nevada
77% of the ice gone
Glaciers94 → 64
Area12.2 → 4.4 km²
Source: PNAS 2026
Rockies
Montana and Wyoming
Wind River, WY116 → 74
Lewis Range, MT176 → 145
Source: PNAS 2026
Why
A double whammy
Hotter summers melt more ice, and winter rain replaces the snow that once fed it.
Why it matters
Late-summer water
Glacier melt keeps streams cold in the driest weeks, vital for fish such as bull trout.
By 2100
Only the tallest peaks
Many remaining glaciers may be gone by 2100, surviving only on peaks such as Rainier and Hood.
Source: Andrew Fountain, PSU