The Botany of Iceland - 01.12.1942, Blaðsíða 20

18
JOHS. GRONTVED
sea to a height of 400—500 metres. The plateau of the Vestfirðir
pcninsula has an average height of about 600 m, and towards the north-
east the summit of Drangajökull rises 925 m above sea-level. The area
of this jökull is about 350 sq.km. On the Vestfirðir peninsula there is
practically no lowland save for a narrow border of coastal land.
G 1 a c i e r s. The Icelandic climate is especially adapted for the
development of large glaciers, due to the cold and moist air, the large
amount of precipitation, and the relatively low temperature in the
summer. The precipitation attains its maximum towards the south-east
(cp. p. 36), and here the interior highland is covered by the largest
of the snow-fields, Vatnajökull, with an area of about 8,500 sq.km,
thus occupying most of the south-eastern part of the country. The
highest mountain in Iceland, the volcano Öræfajökull (2119 m), is
situated in the south-westem part of Vatnajökull.
North-west of Vatnajökull is Hofsjökull with an area of about 1400
sq.km, and again west of Hofsjökull is Langjökull, extending from the
S.W. to the N.E., with an area of about 1100 sq.km. Of other glaciers
may be mentioned Mýrdalsjökull (with a spur Eyjafjallajökull towards
the west) ; this glacier covers the country north of Vík on the south
coast, its area is estimated at about 1000 sq.km. On the Snæfellsnes
peninsula lies Snæfellsjökull, and on the Vestfirðir peninsula Drangajö-
kull.
Ok and Eiríksjökull, to the west and north-west of Langjökull
respectively, may also be mentioned, as also Torfajökull north of
Mýrdalsjökull. Tungnafellsjökull may be regarded as a somewhat
isolated north-western portion of Vatnajökull. The total area of the
Icelandic glaciers is, according to W. Hering, 1935, p. 11, estimated
at about 13,400 sq.km, or about one-seventh of the entire area of
Iceland.
When eruptions of the volcanoes hidden under the ice take place,
the so-called Jökulhlaup (glaciers-torrents) may cause great cata-
strophes. Huge masses of ice are then broken off and meltcd, and often
large stretches of land lying below the glaciers are inundated by the
water which is able to carry with it immense quantities of gravel and
sand, large pieces of rock, and even icebergs. Such inundations fre-
quently change the surface of the country, whole parishes or large areas
of land have been destroyed, the course of rivers is often changed, and
smaller fiords have been filled up even in historic times. Thus the
volcano Katla in Mýrdalsjökull has been the cause of great destruction
in inhabited areas, and the same is the case with Öræfajökull. Skeiðarár-