Measurements of velocity and ablation from Bering Glacier during the recent surge

Document Type

Conference Paper/Presentation

Publication Date



Bering Glacier, in south central Alaska, the largest and longest glacier in continental North America, is once again surging. The last surge occurred in the 1993-1995 time period; the current surge was first documented by satellite observations in January 2011. In mid-May 2011 we deployed Glacier Ablation Sensing System (GASS) units at six sites from the terminus (sea level) to the Bagley Ice field (1200m). At each GASS site the date, time, GPS WAAS enabled location, air temperature, melt, wind speed, upward and downward looking light intensity are measured and recorded on an hourly basis. The melt is determined by measuring acoustically the distance between the sensor's housing which is mounted on an aluminum pole stream drilled approximately 10 m in to the ice or snow surface. Two of the GASS sites nearest the terminus transmit data back via the iridium network and are reported on the web (www.beringglacier.org - click on 2011 ablation monitoring). As of late July 2011, the glacier had moved approximately 785m at the terminus (B1) and 858m at B2 approximately 15 km up glacier at an altitude of approximately 340m. B1 total melt from mid-May was 494 cm, while B2 melted 383 cm. From previous observations, the average daily melt at Bering in the summer is approximately 5cm/day, and the velocity at B2 was 4.5 m/day, with a total displacement in 2010 of approximately 280m. B2 is presently moving 12m/day down from its peak observed displacement of 18m/day in late May. In late July, B1 at the terminus is moving approximately 7m/day, slower than its maximum daily displacement of over 15m/day observed in late May. In contrast, the 2010 GASS unit measurement at the glacier terminus observed a daily movement of only .14m/day with a total displacement of only approximately 10 meters. The hourly observations for all six GASS units will be presented along with interpretation as to why the melts and displacements vary over the observation period.

Publisher's Statement

© 2011 American Geophysical Union.

Publication Title

AGU Fall Meeting 2011