We did a short day trip to Kleine Scheidegg (on the way to Jungfraujoch) to see how well we can measure the flow of hanging ice with a ground based radar interferometer. This is a nice instrument, built by Gamma Remote Sensing that can measure displacements as small as a few millimeters. In the case of Eigergletscher it took a few hours to get sufficient displacements.
The radar, ready to go.
And here is Eigergletscher as seen by the radar. The picture shows an interferogram taken from two images separated by several hours. The colored fringes near the center correspond to 8 mm of motion for one color cycle. Since we can count about three cycles, that corresponds to 24 mm of displacement.