Jökull - 01.12.1964, Side 21

vance occurred, but alrnost certainly it was dur-
ing the late summer and autumn of 1945, and
contemporaneous with the advance of Tungnár-
jökull. On the map fig. 12 the extent of the
crevassed area is shown approximately. When
the present writer first visited the margin of
the Southern Tungnárjökull, E of Jökulheim-
ar, in July 1953, it was a gently sloping re-
cession front, and it is unlikely that it was
affected by the 1944 advance to the sarne de-
gree as the margin north of Kerlingar.
DYNGJUJÖKULL 1951
After the sudden advance in 1934 the front
of Dyngjujökull gradually grew thin again.
When visited by Fr. Nusser July 18, 1939, the
angle of slope of the glacier margin at the
place, where the photo fig. 1 was taken in 1935,
was about 25° (Jonas, op. cit., fig. 80), but the
margin was still very near to the 1934/35
moraines.
In 1946 the present writer participated in an
expedition to Grímsvötn via Ódádahraun—
Dyngjufjöll. August 4 we reached the glacier
margin short W of Holuhraun. The glacier
front was then very gently sloping, and two
jeeps and a trailer were driven 18 km across
the slightly crevassed ablation area to the tem-
porary firn lirnit, 1230 m above s.l. (Thorarins-
son and Sigurdsson 1947, p. 64). Within the
accumluation area we met no crevasses. The
glacier surface was still smooth when the crew'
of the passenger plane Geysir, which crashed
on the N slope of Bárdarbunga, was rescued in
late Sept., 1950. Together with other members
of the French-Icelandic expedition J. Eythórs-
son visited the accumulation area of Dyngju-
jökull April 8 and 9, 1951 (Eythórsson 1951, p.
13). He feels rather certain that crevassing had
not begun by then (pers. comm.). But in early
August that year, when G. Jónasson for the
first time drove a car along the margin of the
glacier, its entire front west of Holuhraun was
very steep and high (pers. comm.) and when
the present writer drove with Jónasson the
same route July 15, 1957, and again visited
Dyngjujökull July 24, the front was still very
steep in places, and the recession from the
1951-moraine had just begun. Reconnoitring
flights over western Vatnajökull 1954 and later
showed that the main part of Dyngjujökull,
but especially its western part, was badly
crevassed in similar way as described by Jonas
and Nusser in 1935.
From the above said we can conclude that
during the spring and early summer of 1951
Dyngjujökull advanced in a similar way as in
1954.
Fig. 3. Skaftárjökull Feb. 24, 1946. Aerial view towards W. — Photo: S. Thorarinsson.
JÖKULL 1964
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