Measures in Time: Explore the Virtual Museum Further Reading

Photographs of the Terminus

A detailed search has been made to locate and examine photographs that show the terminus or margins of the Illecillewaet Glacier. This has included careful search of the published literature, searches assisted by archivists (e.g., at the Whyte Museum of the Canadian Rockies, the British Columbia Archives and the McGill University Archives), searches of federal and provincial aerial photography and examination of photographs held in collections at Glacier National Park and at the National Hydrological Research Center at Saskatoon, the Glenbow Museum, McCord Museum, Canadian Pacific Limited Archives, American Alpine Club and the Detroit Publishing Company. These collections have dozens of photographs that provide firm dates and good ground control for 1888 to 1912 glacier termini, but no precisely dated photographs of the ice front were found for the years 1912 to 1931. Repeat photographs of the terminus from 1945 to 1962 can be found in the D.W.P.B. survey reports. Details of the surveyor’s notes and description of potentially useful photographs of the terminus are listed in Appendices 1 and 2. Aerial photographs are listed in Table 1.

Table 1: List of aerial photographs that show the terminus of the Illecillewaet Glacier.

Photo # Date Flying Ht.
(feet)
Lens
(inches)
Approx. scale
(at 1887 moraine)
A11717 86 19/9/48 20000 6 1:26850
A12223 273-276 - /8/49 20000 6 1:26850
BC1383 16-21 14/9/51 20000 81.38 mm  
A13252 145-146 19/8/51 35000 6 1:70000
A13323 40 6/9/51 35000 1:70000
BC1623 74-78 2/10/52 20000 81.38 mm  
A15985 116-117 8/6/58 10500 6 1:21000
A18748 37-39 2/24/65 18000  
A19430 109-111 23/8/66 30000 1:30000
BC5391 102-103 1970 30000 1:80000
A22442 28-29 16/9/71 45000  
A24520 96,106,107 25/7/76 34000 1:30000
A24972 12,14 24/7/78 19500 1:25000
A31215(colour) 24/7/78 19500 1:25000
A24973 15 2/8/78 19500 1:25000
30BCB 91175, 64 1991      
A27988 90,97 8/8/93 33000 1:30000
B96078 10/9/96 27010  

Photo numbers with the prefix “BC” or “B” are available from the Government of British Columbia or its authorized sales outlets; all others are available through the National Air Photo Library of Canada.

Reoccupation of camera positions used by government survey parties in 1946 through 1956 (Collier, 1958) shows that by 1986 (Figs. 7,8,9) the glacier had thinned by about 5 m and was within 1 m of its 1948 position along most of its perimeter.


Employees of Parks Canada have also monitored annual fluctuations of the icefront. In 1972 six small, hexagonal-headed brass “pins” were placed in small patches of concrete near the glacier terminus (Klewchuk, 1972). The resurvey of the icefront in 1973 discovered that the glacier had advanced several meters since 1972. Since no surveys were done in the previous decade it is unknown when the advance began. The naturalist’s observations are summarized in Figure 10.


Their report does not provide photographs or maps that can be used to help locate the reference pins, but the following description was provided: “Pin “P” is located on a fairly prominent knoll to the South of the toe. Pin “2” is close to the small pond of water which forms annually at the very edge of the ice, on the south side of the toe. Pin “4” is close to the bedrock which has been painted with the figures RP 14. Pin “N” is near the top of a fairly prominent small knoll West of the toe.” (Klewchuk, 1972: 3). In August of 2002 large cairns were found at these pins.

Unfortunately, the use of the reference pins was abandoned in 1973. Parks Canada has continued to use repeat photography to monitor changes at the ice front. Oblique and aerial photographs taken since 1986 are now being analyzed to reconstruct frontal activity since 1986. Ice front positions mapped from historical ground and aerial photograph are shown in figure (Figure 11).


 

Icefront Maps Botanical and Geomorphic Evidence of Glacial Activity

 


Figure 6: Simplified version of the map produced by Collier (1956) to show frontal changes at the Illecillewaet Glacier from 1945 to 1956. The map has been redrawn in colour and the survey points are not shown.


Figure 7: The terminus of the Illecillewaet Glacier in 1952 (Brock, 1952. Image 2375A)


Figure 8: Illecillewaet Glacier as seen in 1958. Source: Ramsden, 1958: “Illecillewaet Glacier from R.P.3.”


Figure 9a


Figure 9b

Figure 9: Comparison of the 1986 (a) and 1948 terminus (b). Arrows show the same rock near the ice. Notice that the top of the bedrock has been scoured by the ice while the darker areas were not scoured and have undergone chemical weathering. Photo sources: (a): Dan McCarthy, July 1986; (b): Smith, 1948: “Panorama Illecillewaet Glacier from R.P. 2.” 1947.


Figure 10: Map showing frontal activity mapped by naturalists in 1972-1973. The four pins closest to the ice were stamped with the numbers 2, 3, 4 and 5. The others were stamped with N and P. This map is based on data and maps in Klewchuk, 1972 and Silverstone, 1973.


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