As has been the custom of the naturalist department for the past number of years, the recession of several major glaciers of Mount Rainier was measured during the last days of August and early part of September of this year. The past winter was more normal in snowfall than the winter of 1933-34 and in addition the past summer was also more normal in regard to its weather and open period. Consequently the backward movement of the glaciers measured was considerably less in most instances than was the recession for the year 1933-34. This was particularly noticeable in the case of the Nisqually Glacier which in the preceding year (1933-34) set a maximum recession record of 155 feet. During the past year a recession of 54 feet was tabulated which is somewhat under the normal annual recession, in the case of the Nisqually, of approximately 70 feet.
As is usually the case the recession of the Carbon Glacier was far less than that of any other as this "river of ice" is protected from the intense heat of the sun by the narrow gorge in which it lies for all but a few hours of each day. In the case of the Stevens Glacier the marker that was placed in position last year was either washed away or was still covered with snow as it was not found. Consequently no recession record is available for this glacier for the past year. A new and more permanent point was established this fall. The Paradise Glacier changed very little in general appearance though it had receded in the usual manner. As this glacier presents a wide ice front, recession here is measured from three points and one of these was still covered with snow so that it was not possible to obtain this record from all three established points.
Recession records for each of the glaciers measured are tabulated below:
* Data from reliable historical accounts.
Several attempts were made to establish permanent points for recession measurements but each was destroyed until 1932 when the point was finally permanently established.
SOUTH TAHOMA GLACIER
The South Tahoma Glacier changed considerably in appearance in so far as the character of its snout or ice front is concerned. It was apparent that a "washout", such as occur red on the Nisqually last fall and which damaged the concrete bridge spanning the river, also occurred on this glacier. At the point where the stream formerly emerged from the ice there was merely a great mass of debris that had been washed into position by the head of water that no doubt accumulated upon the surface of the ice during the extremely wet period in the fall of 1954. The river had changed its point of emergence and now was issuing from the ice at a point nearer the left side of the snout which presents a wall of ice to view approximately 90 ft. in width and in places over 100 ft. high. Anticipating this change in the point of emergence of the stream a point was established last fall which was at that time 142 ft. from the ice. This year it was 184 ft. from the ice which showed a recession of 42 ft. at that point. Recession from the former established point in past years is as follows:
The point established last year was not found. It was either washed away or otherwise destroyed or was still covered with snow. Consequently a second point for future measurements was-established. A large molin which was one of the interesting features of this glacier last fall and which occurred near the snout had melted out during the past year.
The recession of the Emmons Glacier, which is the largest glacier on Mt. Rainier and has the reputation of being the largest glacier in the United States (exclusive of Alaska), was measured on August 30, 1935. Some major changes had occurred in the appearance of the snout of this "river of ice" in the past year and it was deemed advisable to take data on two points. The river had apparently changed course several times during the year and water-born debris had collected on the flat immediately in front of the snout to a considerable depth. The stream emerged from the ice through a large tunnel or cave near the left flank of the ice. To the right of this point the ice rose in a sheer wall. It is very likely that a large head of water was discharged from the surface of this glacier during last fall's heavy rains as was the case on the Nisqually in the fall of 1934.
It seems likely that the ice will recede most rapidly during the next year at the point where the large cave is now located, the ice being thinner there and greatly broken up.
Tabulation of recession data follows:
* Recession was measured in two points. From line of site to point where the stream emerged the recession was 67 ft. The second point - from line of site to ice wall to right of cave - showed a recession of 30 ft. The average is thus 48.5 ft. for the past year.
C. Frank Brockman,
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