Record high early summer temperatures, heat-absorbing soot, and diminishing winter snowfall colluded to melt Alberta’s Saskatchewan glacier by more than 10 metres this past year, CBC reports.

“It clearly is the most extreme melt we’ve seen,” said Brian Menounos, glaciologist at the University of Northern British Columbia.

Since 2017, researchers have surveyed 400 western Canadian glaciers twice per year to measure changes in glacial thickness and elevation. This year’s melt from the Saskatchewan glacier exceeded all records, including observational records from long before 2017. Researchers expect that most of the glacier will be gone by the end of the century.

Much of the melting was caused by heat waves in June. The high temperatures were compounded by the long daylengths of early summer, which offered less time for temperatures to drop overnight. The year’s formidable fire season also released soot that accumulated on the glacier’s surface to darken it and absorb more sunlight. 

As well, reduced snowfall in recent winters has allowed the glacier to melt faster by not providing a buffer to protect the ice from sunlight, writes CBC. “Solar radiation is extremely effective at melting snow and ice and converting it to water,” said University of Alberta glaciologist Martin Sharp.

The glacier feeds the Saskatchewan River, a source of drinking water for Edmonton and other communities in Alberta. Roughly one in four Albertans will experience water shortages as the Saskatchewan glacier—and others—disappear, the news story states.

The loss of cold glacial water into the river will also disrupt thermal buffer zones that create habitats for species of coldwater fish.