Figure 1: Tweedsmuir Glacier in retreat
(Shangaan Webservices Inc, http, 2006).
- 1973 (April): Tweedsmuir began to advance at its terminus (USGS, 2002).
- 1973 (June/ July): peak activity in advancement occurred due to basal sliding (USGS, 2002).
- 1973 (22 July 1973- 13 September 1973): advancing ice speeds were measured to be about 10m/day (USGS, 2002).
- 1973 (winter): the large, piedmontlike lobe expanded and dammed the Alsek River temporarily (USGS, 2002).
- 1973: ice cliffs at the river contact were roughly 25-30 m high and on the northern inland sublobe, thickness was about 15m. Thickness in the center was probably 50-100m (USGS, 2002).
- 1974 (summer): The Alsek River flowed passed the Tweedsmuir, causing extreme ice calving into the river (USGS, 2002).Figure 2: Ice flow lines and vectors 1973-1978 (USGS, 2002).Figure 3: Ice flow lines based on ice flow vectors, 1973-1978(USGS, 2002).
Location: St. Elias Mountains in the Alsek River Watershed (USGS, 2002).
Characteristics of Tweedsmuir Glacier
Type: surging (USGS, 2002).
Altitude: no data
Width: 1km (USGS, 2002).
Length: 70 km (USGS, 2002).
Volume/Mass: no data
Thermal Regime: warm glacier (surging) (USGS, 2002).
- Other glaciers in the Canadian Alsek Hydrologic System (USGS, http, 2002):
- Dusty glacier
- Lowell glacier
- Fisher glacier
- Verm Ritchie glacier
- Battle glacier
- Melbern glacier
- Tweedsmuir ends in an expanded piedmontlike lobe that is in contact with the Alsek River (USGS, 2002).
- The Alsek River terminates after a 16km stretch of rapids at the point where Tweedsmuir Glacier and Turnback Canyon come together and prevent further water flow ( see Figure 4) (Canadian Heritage Rivers System, 2007).
Figure 4: Tweedsmuir Glacier and Turnback Canyon prevent flow from the Alsek River (Environment Canada, http, 2006)
Canadian Heritage Rivers System, 2007. Alsek River. Available at: http://www.chrs.ca/Rivers/Alsek/Alsek_e.htm (Accessed on 22-02-07).
Environment Canada, 2006. Barrier to Salmon Crumbles on the Alsek. Pacific and Yukon Region Archive Columns. Available at: http://www.taiga.net/yourYukon/col466.html (Accessed on: 21-02-07).
Shangaan Webservices Inc., 2006. BC Parks-Tweedsmuir (North) Provincial Park, Chilcotin. Available: http://www.britishcolumbia.com/parks/?id+208
United States Geological Survey, 2002. Glaciers of the St. Elias Mountains. Available at: http://pubs.usgs.gov/prof/p1386j/ (Accessed on 21-02-07). (Accessed on: 21-02-07).