EARLY SURVEYS OF THE VAUGHAN LEWIS WAVE BULGES

The first surveys of the Vaughan Lewis icefall wave bulges were done by Ty Kittridge with a plane table and tape method. In 1969 there were only two benchmarks above the icefall for survey purposes and in that year the author used a T2 Theodolite to measure movement stakes at the base of the icefall recording the first movement velocities along a profile over the first few wave bulges. In 1970 and 1971, the first coordinate system was placed over the Gilkey Glacier basin where the Gilkey Glacier meets the Vaughan Lewis Glacier and flows downward toward Berner's Bay. This coordinate system was measured with the T2 Theodolite and an early microwave distance meter. This triangular coordinate system spanning the "Gilkey Trench" was used to measure movement stakes across the Gilkey, Vaughan Lewis and Unnamed Glacier. The results of these first ever measurements of flow velocity in the Gilkey Trench are presented along with anecdotal history of the early years of the Juneau Icefield Research Program.