'Military Report on Mesopotamia (Iraq)' [‎16r] (36/226)

The noteworthy point with regard to temperature is
the wide range, viz., from freezing point to 115° F. From
June to August the heat during the day is almost unbear
able, but the nights are comparatively cool. Snow has
been known to fall in winter to a depth of 10 inches
(February, 1920).
The following deductions are made from the above
facts, and the experience of columns operating in the
district:—-
(i) Between May and October the heat, combined with
lack of rain, drives the nomad tribes to the north of
Northern Jazirah, and this practically frees the Mosul-
Shergat lines of communication from anything but long
distance raids.
(ii) Between May and October marches should be carried
out during the night, or in the early morning or late
evening.
(iii) Sun helmets and glare glasses are necessary to
combat the heat in summer.
(iv) In winter, movement is possible by day and by
night.
(v) British winter scale of clothing and blankets are
necessary in winter months.
Winds .—The general direction of winds throughout the.
year is north-west. During the winter, however, and also
in the summer, the wind occasionally veers to the south,,
and then it tends to be enervating. The prevailing wind,
passing over the plateaux of Anatolia Peninsula that forms most of modern-day Turkey. and Kurdistan,
descends upon the Jazirah as a dry current of air, which
rapidly heats up as it leaves the mountains. Calms are
of unusual occurrence, and it is the general rule for the
wind to attain its maximum velocity during the day.
During the summer sand-storms frequently occur, but
are neither so uncomfortable nor so heavily laden as those
in the south of Iraq. Another common phenomenon in
summer is the mirage, which distorts the landscape, often
with grotesque and unrecognizable shapes.
The following are the military effects of atmosphere and
wind : —
(I) Conditions affecting Aviation.—(a) The air during
the summer months is less dense in Northern Jazirah
than in Europe or Northern Egypt, thereby reducing the
performance of the machines. Machines climb more
sluggishly and have to glide faster to maintain control.
They can climb high enough, however, to clear most hills
in the area even when loaded with bombs, Lewis guns and