GRAND TETON NATURE NOTES

ICEFALLS FROM FALLING ICE GLACIER, MOUNT MORAN

by Fred D. Ayres

On August 13, 1934, a tremendous mass of ice broke off the face of Falling Ice Glacier and slid far down the talus slope below, leaving a broad white trail of broken fragments nearly a quarter of a mile long. Since an ice slide of this magnitude was a rare occurrence, it was deemed worthwhile to make the long climb up to the glacier in order to get a closer view. However, other climbs prevented a start before the morning of the eighteenth, and by this time a considerable portion of the fallen ice had melted away.

From the Leigh Lake snow shoe cabin a course was followed which contoured around the base of the east buttress of Mount Moran to the long talus slopes below the glacier. From here it turned upward to the rounded brown pinnacle, a remnant of the great dike, north of the morainal slope and several hundred feet below the glacier. The view from this pinnacle is one of the finest to be had of the glacier and now, with an entirely fresh wall of glacial blue extending all the way across from one to the other of the two great rock towers from between which the glacier emerges, it was certainly at its best. As wide as the face of the glacier itself the path of broken ice extended from the ice wall down the slope to the pinnacle and on for an equal distance below.

MOUNT MORAN AND FALLING ICE GLACIER
from photo by Harrison R. Crandall

Some photographs from a closer viewpoint were desired so the pinnacle was descended in the direction of the broken ice. Upon reaching the edge of the slide the huge size of the ice blocks, many of them several feet in diameter, and the magnitude of the slide in general caused the writer to pause and reconsider the situation. To be caught out on this jumble of ice in the event of a second slide would be disastrous. Finally, rather than climb far down below around the bottom of the slide he decided to risk the dash across. It proved to be not so bad for the blocks were much smaller in the center than at the edges of the slide. From the opposite side, by following a series of ledges and slabs on the south wall below the cirque, the outcropping of the dike directly at the south end of the ice wall was reached. Here descent was made to a strip of talus slope along the rock wall of the dike not covered by the ice slide and further approach accomplished by dashing from the shelter of one overhang to the next. Fortunately there were plenty of them. Finally the advance was stopped completely by the failure of the overhangs, and the proximity of a rock bombardment which was spraying almost continuously over an area directly ahead. Several rocks whizzed overhead and struck the talus slopes below. However, these did not cause much worry because of the general overhang of the dike above. The rocks wore presumably set in motion by the rush of muddy water which was pouring down along the wall of the cirque from somewhere high above.

From this close viewpoint the entire northern portion of the ice wall was seen to be leaning far outward, and seemed almost on the point of breaking off. In addition the whole leaning mass was perched on smooth, steeply sloping slabs. A number of photographs were taken from this position. Suddenly from high overhead were heard heavy, staccato reports, followed by complete silence. By this time the writer had already ducked back under a projecting ledge for all climbers well know the meaning of this warning signal. Almost immediately a huge boulder, some two feet in diameter, came hurtling into view and crashed onto the rocks fifty feet out on the talus slope. The fragments set flying by its impact clearly indicated that a hasty withdrawal from this advanced position would be discreet. A rapid descent was accordingly made back to the pinnacle (this time by the more laborious route down around the bottom of the slide).

Since another ice avalanche was clearly just on the verge of starting, the writer got his camera ready and perched on the pinnacle hopefully waiting for more than two hours. However, nothing happened other than the incessant rattling of rocks down over the dike. This rattling was punctuated frequently by bursts of large boulders which filled the canon with their echoing. By this time it was growing late, so return was made to Jenny Lake. Sometime during the night the expected slide occurred. Frank Swenson, Reynold Holinen, Irene Ayres and the writer made the climb up to the glacier to examine the results. This second slide proved to be much less spectacular than the first. It was fully as long, but scarcely one fourth as wide as the first. The rock bombardment observed on the first trip was still in full swing. It seems to be a regular feature offered by the glacier.