15 July, 2000

July 15, 2000

Today Andrew Fountain and I returned to our former drill site on the ice dam. There are three boreholes at that site that have pressure transducers placed in them. Two of the holes have completely filled with water. In the third borehole the water is well below the surface, but it was impossible to measure. The hole had an impermeable layer of ice at about 6 meters down. Andrew and I attempted to break through this layer with a hand drill, but we had no success. What was interesting to observe were the changes in the crevasses over the past five days since I was last there. I spoke of, and included pictures of some crevasses for my journal entry of July 8. At that time some crevasses were opening in the vicinity of our former camp and had opened to about 4 inches. Today, these crevasses had opened to 18 inches. I include pictures below to show the type of change that can occur to ice over a short period of time - especially when subjected to the extreme pressures of an adjacent lake on the rise.

Photograph of the same crevasse shown above, but taken on July 15. This photo was also taken from a greater distance. The crevasse has opened to about 18 inches. PI Andrew Fountain (PSU glaciologist) is checking the instruments in the two boreholes in the lower left of photo.