Lieutenant JG Laurel Jennings and Survey Tech Matt Boles of the Rainier conduct a CTD cast near the face of Hubbard Glacier. CTD casts measure temperature, salinity and pressure in the water column and are used to estimate sound speed through water. The change in sound speed through water is one of the correctors applied to multi-beam echosounder data to improve depth accuracy.
|In September of 2006, the NOAA Ship Rainier conducted a special hydrographic survey of Disenchantment Bay located just north of the town of Yakutat, AK per request of scientists from the University of Alaska and the USGS. Disenchantment Bay is home to Hubbard Glacier, the largest tidewater glacier on the North American Continent. Multibeam sonar systems mounted on the Rainier and her launches were used to collect bathymetry data near the face of the glacier.The survey was conducted to assess any changes in seafloor topography following the substantial advancement of Hubbard Glacier in recent years. Disenchantment Bay was last surveyed by the Rainier in 1999, and since that time, the glacier face has advanced significantly beyond the charted terminus, up to 600 meters at some locations.Hubbard Glacier is a popular tourism destination, and is visited frequently by large cruise ships in the summer season.|
Hubbard Glacier has been advancing seaward for about a century. In July of 2002, the glacier’s terminal moraine pushed forward far enough to dam the entrance to Russell Fjord.The dam was breached that August following a period of heavy rains.