The Botany of Iceland - 01.12.1914, Blaðsíða 105

PHYSICAL GEOGRAPHY
289
Iceland the snow-covering persists so long during winter, that all
intercourse between the farmsteads takes place on snow-shoes, and
goods are transported on sledges, but in South Iceland sledges are
hardly ever seen and still less snow-shoes. Snow may fall in anv
of the surnmer months, but in South Iceland it is only rarely that
tliere is snowfall of any consequence during summer. In the
northernmost districts it happens now and then, especially when
Polar ice is in the vicinity of the island, that it snows so heavilv
l'or some days during mid-summer, that haymaking is suspended
and the cattle must be stabled for a shorter or longer time. On
the plateau snow-storms accompanied with frost occur now and
then in .July and August, arnl upon the great ice-mounlains (Jökulls)
it often snows in all months of the vear. During a period of 30
years it snowed on an average 84 days annually at Stykkisholm,
44 days in the Vestmannaeyjar, 50 days at Berufjord, 45 days on
Papey and 64 days on Grímsey. The amount of snow, as already
mentioned, varies greatly according to the vear. Snow-storms during
winter have often caused great disasters by destroying thousands
of sheep and many human lives. The annals of Iceland give us
much information of such disasters, and numerous written records
of many centuries sliow that the climate of Iceland has not changed
since its first colonization in the year 874.
Hail is fairly common during winter, but rare during summer.
On Grímsey it hails about twenty-four times annually; in the Vest-
mannaeyjar twenty times, at Stykkisholm five times and on Papey
twice. The hail-stones are as a rule small, rarely larger than grit;
but during volcanic eruptions, they are much larger, and often
include grains of volcanic sand or aslies. Thunder is verj' rare and
occurs as a rule only in winter. The registered thunderstorms average
two in the year in the Vestmannaeyjar, and only one at Stykkis-
holm and Berufjord, while none have ever been registered on Grímsey.
On the whole, thunderstorms are extremely rare in northern Ice-
land; thus at Audkula vicarage, in the district of Húnavatnssysla,
thunder was heard once only between 1857 and 1873. Thunder-
storms are more common along the southernmost part ol’ the coast
(Eyjafjöll, Landeyjar, Rangárvellir) where they occur sometimes during
the summer also. The volcanic eruptions are almost alwavs accom-
panied by thunder and strong electrical discharges.
The climatic conditions we have hitherto been considering, have
naturally been those connected especially with the coasts and the