The Botany of Iceland - 01.12.1914, Blaðsíða 104

288
THORODDSEN
of Berufjord) there are 143 foggy days. In other places fogs are
much rarer; for instance on Grímsey there are on an average 46
foggv days, the majority of which occur during summer, while at
Stykkisholm there are only nine. Along Hornstrandir fogs are very
common especially during ice-years, but from this locality no ob-
servations are to hand.
The amount of snow varies greatly according to situation and
height above sea-level, and from year to year. In North Iceland
snow often persists for a long time during winter, but in south-
west Iceland the weather is always stormy and unsettled; conse-
quently, in the lowlands the winter-snow rarely persists for a long
time. Frost and thaw often alternate daily. In South Iceland it
often happens during winter that no snow is to be seen for months
in the lowlands. On the other hand, it rains very often, and the
preeipitation which falls here as rain, produces on the plateau con-
siderable masses of snow. By way of exemplifying the durability
of the snow-covering, I give the results of my observations — the
number of days with snow-covering — in Reykjavík during the
winters of 1889—1892 and 1893—1895 in the following table: —
1889 —90 00 O 1 co 1891—92 1893—94 1894—95
September 0 0 0 2 0
October 2 4 1 2 1
November 9 10 10 5 2
December 23 12 26 27 23
January 31 13 25 14 18
February 15 13 29 28 3
March 16 30 24 14 8
April 0 2 6 0 5
96 84 121 92 60
In these five winters it snowed for the first time on Oct. 28,
Sept. 28, Oct. 24, Sept. 19 and Oct. 31 respectively; for the last time
on March 20, April 18, April 26, March 30 and April 18. Very often
the snow persisted for a day or two only. The longest period during
which the ground was covered continually with snow, w7as in the
winter of 1891—92, viz. 63 days, from Jan. 19 to March 21. In all
these winters tlie neighbouring Akraíjall, which has an altitude of
364 metres wras often entirely snowdess. In several places in North