Arapaho Glacier РApril 3, 2019

Today’s “Science Wednesday” is from the Arapaho glacier in Colorado. Back in 1919, the glacier was pretty full, healthy and even had deep crevasses, as you can see in the historic photo below. In the early 20th century, the city of Boulder purchased a watershed of dammed-up lakes fed by the Arapaho Glacier. A $200,000 pipeline was installed to bring the “99.996% pure” water into town. The Hotel Boulderado’s drinking fountain (also pictured below) is the only one left today.

Unfortunately, Arapaho Glacier lost 52% of its area during the 20th century, decreasing from 0.34 to 0.16 square kilometers. If recent trends in area loss continue, Arapaho Glacier may disappear in as few as 65 years! However, a decline in thinning rate suggests that the glacier is retreating into a corner of its upper cirque in which increased inputs of snow from direct precipitation and avalanching, and decreased solar radiation will greatly slow its rate of retreat and melt. Sadly, though, there’s still not enough water from Arapaho glacier to serve the city of Boulder anymore.