New Colorado State University measurements show the same squeeze Swiss monitors recorded: record-low snow followed by record heat, and a shrinking summer water buffer.

Update Note: This article reports new information involving 2026 glacier losses following Nature World News' earlier coverage of the Swiss GLAMOS report. Latest verified sources: Associated Press report on Colorado State University measurements, published Oct. 27, 2026, and an ETH Zurich release on the GLAMOS findings published Oct. 23, 2026. Figures cover the 2025 to 2026 glacier year.

Colorado's best-known glaciers lost ice at twice their recent pace this year — and one popular snowfield vanished outright. Andrews Glacier in Rocky Mountain National Park thinned by more than 12 feet (3.7 meters) in a single year, Arapaho Glacier lost nearly 10 feet (3 meters), and Isabelle Glacier about 6.5 feet (2 meters), according to Colorado State University glaciologist Dan McGrath, the Associated Press reported on Oct. 27.

The losses came after Colorado's worst snowpack on record and a record-hot summer. St. Mary's Glacier, a perennial snowfield popular with hikers and backcountry skiers west of Denver, melted away completely in September.

The Colorado numbers echo what Swiss scientists confirmed this month. Switzerland lost nearly 20 percent of its glacier ice volume in five years, and the same pairing of thin winter snow and long summer heat drove both. For Western households, the practical question is what happens to late-summer streamflow when that ice is gone.

Rocky Mountain Ice Losing Ground Fast

McGrath's measurements show thinning rates for the three named glaciers doubled compared with the previous five years. In the decade before that, they typically thinned a foot or less per year. Andrews Glacier has lost about half its ice since 2017.

"These glaciers are out of balance with the climate here in Colorado," McGrath told the AP. At the current rate, he estimates Colorado's remaining glaciers could disappear within about 20 years.

Colorado's glaciers are small, and they are not a major share of Front Range water supply in the way snowpack is. They matter most in the driest weeks of late summer, when meltwater feeds high alpine streams, wetlands and the plants and animals that depend on them. The National Park Service studies these glaciers and snowfields in Rocky Mountain National Park for that reason.

The same AP report noted the fastest average glacier retreat on Washington's Mount Baker since 1950, according to Mauri Pelto of the North Cascade Glacier Climate Project.

Swiss Measurements Show the Same Squeeze

Nature World News previously reported that Swiss glaciers lost 5.5 percent of their ice in 2026, the second-largest annual loss on record after 2022, with record melt on the Rhône, Aletsch and Clariden glaciers. The annual report from the GLAMOS monitoring network and the Swiss Academy of Sciences also found that the country lost nearly a fifth of its glacier ice between 2021 and 2026.

An ETH Zurich summary published Oct. 23 added detail on what drove the year. The freezing level rose above 4,000 meters (about 13,100 feet) on 76 days, more than twice the usual number and a Swiss record. By September, snow had vanished even at 3,500 meters, exposing ice that normally stays covered. Two small glaciers, Bella Tola in Valais and Griessfirn in Glarus, disappeared entirely.

GLAMOS measures a set of reference glaciers each September, then extrapolates to the roughly 1,300 glaciers in Switzerland. Average thickness fell 2.5 to 4 meters this year, and some lower glacier tongues lost up to 10 meters. The network publishes maps and comparison photos on its site, and the AP report includes side-by-side images of Colorado's St. Vrain, Isabelle and Arapaho glaciers.

A Shrinking Summer Water Buffer

Between July and September, Swiss glaciers released about 2.2 trillion liters (roughly 581 billion gallons) of meltwater, more than four times the annual drinking water use of Swiss households, according to ETH Zurich. That flow eased summer water shortages this year. But scientists say the extra water is temporary — each year of heavy melt leaves less ice to melt later.

The same pattern applies, at a smaller scale, in the American West. Glacier runoff supports high alpine ecosystems and downstream flows during drought, and the AP reported that losing it could leave those areas more vulnerable in dry years. Communities that depend on late-summer streamflow, along with anglers and outfitters on high-country streams, are most exposed.

Hazards change as ice retreats. Thinning glaciers and thawing ground can loosen rock on steep slopes. In Switzerland, the village of Blatten was destroyed in 2025 when a glacier collapse brought down part of a mountainside. Hikers and climbers in Colorado and the Alps should expect shifting routes, more loose rock, and snowfields that no longer last through summer.

Next Measurements and What to Watch

These figures are field measurements, not projections, though the 20-year outlook for Colorado is McGrath's estimate based on current rates. Year-to-year results depend heavily on winter snow, so a big snow year could slow losses temporarily without reversing the trend.

Residents who rely on mountain water can follow their state's snowpack reports through the winter, since snowpack remains the main driver of supply. Hikers should check park conditions before heading to glacier trails and avoid ice caves and the edges of melting snowfields.

GLAMOS will publish its next annual report next fall. McGrath's team and volunteers plan to keep resurveying Colorado's glaciers each year.

What Readers Want to Know

How much did Colorado's glaciers shrink? Andrews Glacier thinned more than 12 feet, Arapaho nearly 10 feet, and Isabelle about 6.5 feet in 2026.

What caused it? Colorado's worst snowpack on record followed by record summer heat, according to Colorado State University's Dan McGrath.

How much ice has Switzerland lost? Nearly 20 percent of its glacier volume from 2021 to 2026, including 5.5 percent this year, according to GLAMOS.

Does this affect my tap water? Snowpack remains the main source for most Western cities. Glacier melt matters most for late-summer flows in high mountain streams.

Is it safe to hike near glaciers? Expect loose rock and changing conditions. Check park alerts and avoid ice caves and melting snow edges.