The Summit Foundation reports that sheep-wool covers provided preliminary protection comparable to synthetic geotextile after one summer in the Keep It Wool field trial on Switzerland’s Tsanfleuron Glacier. The project installed the covers at Glacier 3000 on June 22, 2026, and says its collected data still require analysis.
A first summer of wool covers on the Tsanfleuron Glacier
Keep It Wool, led by the Summit Foundation with the University of Lausanne and its Centre for Interdisciplinary Research on the Mountain (CIRM), tested locally produced sheep wool as a material for covering glacier ice. The project’s preliminary finding gives wool a promising result against the synthetic cover used alongside it, while the Foundation says the data from the trial still need analysis.
How the field comparison was set up
The team installed two 10 × 10 m wool covers and one synthetic geotextile cover of the same size at Glacier 3000 on June 22, 2026. Stakes in the covered areas tracked snow and ice melt, with measurements taken every two weeks through September.
| Cover in the trial | Material | Number and area | Role in the field test |
| Wool covers | Sheep wool | Two, each 10 × 10 m | Tested as a glacier-covering material |
| Comparison cover | Synthetic geotextile | One, 10 × 10 m | Compared with the wool covers |
A geotextile is a fabric used in contact with soil, ice, or other ground surfaces. Here, it served as the synthetic material in a side-by-side field comparison.
Why test wool against synthetic glacier covers?
The project is exploring whether locally produced wool can be used for glacier protection. The Summit Foundation describes wool as a natural, renewable and biodegradable option. It says synthetic glacier fabrics made from polyester or polypropylene can shed fibers through wind, precipitation and wear.
A local cover test in the wider glacier picture
The Foundation estimates that existing geotextile covers protect about 0.02% of Swiss glacier surface and preserve about 300,000 cubic meters of snow each year. Separately, it estimates that Swiss glaciers lose nearly 1 billion cubic meters of ice annually.
The Foundation says localized covers cannot stop long-term glacier retreat and identifies reducing greenhouse-gas emissions as the principal long-term measure.
