of the Mountains
season brings the familiar but fascinating thrill we already knew from
the coming summer holiday. And for a lot of us the mountains are the
place to be.
For Europe the Alps are the most attractive; with the Mont Blanc a
massive; the highest of them all.
Mountains have their own special, unreliable climate. The weather one
side of a
mountain can be totally different from the conditions at the other side.
The föhn wind is famous in the Alps; they are so matched that some
föhn wind is specific for the Alps, but that's not true. The term is
all similar winds.
Föhn (its a German word) is a warm, strong and often very
that often blows at the north slopes of the Alps, but can also be at
The föhn often rises as the first front of a low; moving from the South
France to the Mediterranean. The wind will be south there, blowing warm
air to the Alps. Along the south slopes the air is forced to ascend.
rising air cool down; the water vapour condenses and rain will ruin the
many Italians and French.
On its way to the top of the mountains the air looses much of its
becomes dryer. The temperature down the valleys is always higher than
mountaintop. (Its about 1º C in 100 meter.) In the valleys there's a
low pressure that draws the wind down the mountain. While descending
will become warmer by compression and the wind speed will increase. A
föhn storm can easily reach gale force.
temperature in the föhn, at the north side of our mountain, can grow remarkable
higher in a short time; sometimes about 10º
C, and is much higher
at the other side. The humidity of the air can decline to 20%; these
unknown in the UK.
A föhn can last from less than an hour to even several days.
The high crest of this wind wave leaves a specific formed cloud
called a föhnwall (helm cloud).
about this helm cloud; the helm wind is famous in Cumbria. Its a strong
easterly wind that descends the western slope of the Cross Fell Range
But its a föhnwind, caused by an north-easterly flow; the ideal setting
is a moderate,
stable NNE to E wind.
Near Penrith it ceases abruptly, but its roaring can still be heard.
föhnwinds can cause trouble to many people. They get sick, have
nights or a lack of concentration.
Of course there's been a lot of research into these symptoms. It seems
there's a relation to vibrations caused by the waving airstreams. The
prickle the auditory organs, irritating the nerve systems.
A nasty and problematic side effect of a wonderous phenomenon of