Monitoring longitudinal strain

This is one of the two borehole sites that were maintained by ETH Zurich and Hokkaido University on Bowdoin Glacier from 2014 to 2017. This photo illustrates well the challenge or drilling on the terminal tongue of a tidewater glacier. As the glacier flows feet in the ocean, buoyance forces from sea water conteract the weight of the ice. This causes the glacier to accelerate and stretch in the direction of flow. Crevasses seem to pop out of nowhere, sometimes dangerously close to our instruments.