Jökull - 01.12.1964, Blaðsíða 19

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Fig. 1. The front of Dyngjujökull May 25,
1935, 15 km E of Kistufell. (Fig. 29 in Jonas
1948).
(Jonas, op. cit., pp. 166—167). If Jonas’ estimate,
500 m, is not far from correct, it means that
by advancing at a rate of 6 m/day, like it did
towards the end of July 1934, the advance
would have lasted until the end of October
that year. But judging from the condition of
the glacier-margin towards the end of June
1935 it seems likely that its thinning out had
begun before the end of the ablation period
1934. This means — provided that the figure
500 m is approximately correct — that the
maximum speed of advance exceeded consider-
ably 6 m/day.
DYNGJUJÖKULL 1934
When Spethmann visited Dyngjujökull in
1910 a broad belt of its front was a moraine-
covered, dead ice. An enormous ice-cored mo-
raine, stretching across this belt a couple of
hundred meters inside the margin 'indicated
an advance overlapping the dead ice some time
JÖKULL 1964
between 1884 and 1910. The glacier was
distinctly receding in 1884 according to Thor-
oddsen (1905/06, p. 202), and in 1910 the
glacier was apparently receding and thinning
(Spethmann 1912, pp. 419-423).
May 24, 1935, the above mentioned Austrian
expedition reached the margin of Dyngjujökull
about 15 km E of Kistufell. Its front was then
clearly indicative of a sudden advance of the
glacier (fig. 1). The glacier was very crevassed.
Yet it was crossed, though with great diffi-
culties, by the expedition. They found it to be
crevassed also within the ablation area, nearly
to the summit of Kverkfjallahryggur (Jonas, op.
cit., pp. 94—126; Nusser 1936, 1940). As to the
time of this advance of Dyngjujökull it seems
to have come to an end before the Austrian
expedition arrived June 24, 1935, as some of
the photos taken then show that a slight re-
cession from the most advanced stage had al-
ready begun (cf. Jonas, op. cit., fig. 32, and
Woldstedt 1938, fig. 1). On the other hand it
may be regarded as fairly certain that the
advance was not older than from the summer
of 1934. Consequently it is most likely that
this advance of Dyngjujökull, which according
to the descriptions and photos of Jonas and
Nusser, seems to have affected the entire glacier,
coincided approximately with the advance of
Sídujökull in the summer and autumn of 1934.
SKAFTÁRJÖKULL AND
TUNGNÁRJÖKLAR 1945
Sept. 22, 1945, P. Hannesson, Headmaster of
the Grammar School in Reykjavík, and S. Sig-
urdsson, Director of the National Research
Council, went from Reykjavík on a reconnoitr-
ing flight to Grímsvötn, having the day before
received news that a glacier burst had started
in the river Skeidará. From what Hannesson
has written in his diary it is clear that the aero-
plane passed the W margin of Vatnajökull be-
tween Kerlingar and Hamar. He writes: “The
glacier margin was fantastically broken up and
split into high pinnacles.......... crevasses
high up on the slopes” (Hannesson 1958, p.
294).
Oct. 4, 1945, Hannesson ancl Sigurdsson flew
again to Grímsvötn. T his time they passed the
glacier margin just south of Kerlingar, and
from there they flew towards NE. Photos taken
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