Jökull - 01.12.1969, Page 70

Fig. 7. The average monthly surface pressure map for February 1968. From March 5, 1968
to April 6 the ice edge has moved southward about 260 km (about 160 miles). The strong
northerly winds east of Greenland, and the easterly winds over the southern Denmark Strait
may by observed.
from this area. This outflow has two possible
directions of movement, depending on the pre-
vailing weather conditions.
First: The icefield stagnates in the area be-
tween Jan Mayen, Scoresby Sund and Spits-
bergen, while the normal outflow (10,000 km3
per year) drifts through the Denmark Strait
and the melting and breaking up of the ice-
field prevents it from reaching Iceland, except
where it skirts the northwest coast on its way
southward. This is referred to as a normal
situation.
Second: The icefield continues towards Ice-
Iand, mainly because of two factors, namely
prevailing and rather strong north and even
northwesterly winds over the area between Jan
Mayen, Scoresby Sund and Iceland, while pre-
vailing easterly winds over the Southern Den-
mark Strait hamper the normal outflow of the
ice there. This is an unusual situation and
causes the main icefield to drift rather rapidly
— driven by the strong northerly winds and
the East Greenlancl current — to the north
coast of Iceland, hindering all shipping in that
area and cooling the surface water to such an
extent that one can expect but a short herring
66 JÖKULL 19. ÁR