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AVALANCHES
Four fundamental fac-
tors influence the avalan-
che situation. Weather,
terrain and snow cover
are inseparably connec-
ted - these factors in-
fluence each other and
make an evaluation very
complex. Man (Human
factors) and his beha-
vior represent the
greatest uncertainty fac-
tor. The prerequisite for
slab avalanches is cohe-
sive snow (usually drift
snow) in conjunction
with a weak layer that is
sensitive to interference,
on a steep slope.
Only man makes ava-
lanche danger a risk!
TERRAIN
SLOPE FORM
Terrain forms influence
avalanche formation
because they exert a
deciding influence on
wind direction and
speed, and thus the
scope of snow loading.
Thus terrain is the help-
ful partner in evaluating
the avalanche danger.
Good visibility and a lot
of experience are ne-
cessary in order to make
such an evaluation.
Terrain forms influence
avalanche formation.
ASPECT
The slope form (also
referred to as aspect)
influences the tempera-
ture of the snow cover
and its structure. On
shaded slopes (direction
NW to NE) the snow
cover settles very slowly
due to low sun inci-
dence. Existing dangers
remain intact for a
longer period and new
dangers occur.
70% of all avalanche
accidents occur on
north aspects
(W via N to E).
SLOPE
The steepness of a slope
is the essential prere-
quisite for formation of
a snow slab. This factor
plays a major role in the
evaluation and the de-
cision making process.
When determining slope
incline, the steepest
point of a slope should
be considered.
If you do not go to
steep slopes, the
risk of triggering an
avalanche can be
significantly reduced.
WEATHER
PRECIPITATION
The amount of precipi-
tation, (in conjunction
with wind, temperature,
and the existing old
snow cover), is a cen-
tral value to evaluate
avalanche danger.
Critical new snow
accumulation (within the
previous 1-3 days)
10–20cm for unfavor-
able conditions
20–30cm for moderate
conditions
BASIC AVALANCHE KNOW-HOW
Terrain - Weather - Snow pack - Human factors
SNOW COVER
Depending on the
weather situation and
the stability of the ter-
rain differences occur
in the snow cover
(snow slab prerequisites
are "cohesive snow"
and "bed surface").
The following applies:
• Stability on the specific
slope can vary greatly.
• Over so-called hot
spots (very weak slope
areas, where there is
practically no connec-
tion to the underlying
layer), it is particularly
easy for a skier to
trigger the avalanche.
In this case the ava-
lanche can be triggered
by the added load on
the snow pack caused
by one skier.
Alarm signals are:
Breaking noises in the
snow cover (“WUMPF”),
tears in the snow cover,
snow slabs that have
already been released.
Alarm signals indicate
significant avalanche
danger.
HUMAN FACTOR
Man is the most decisi-
ve avalanche factor.
Experience, knowledge,
personal skill, and beha-
vior are also crucial cri-
teria for avoiding avalan-
ches. Conscientious
tour planning, alert
observation and cons-
cious, risk-reducing
decisions are the indis-
pensable components
of any type of off-piste
activity.
The avalanche situation
report is available at
www.lawinensicherheit.de
and www.ortovox.com
or via telephone.
30–60cm for favorable
conditions
New snow accumula-
tion is not the only
deciding criterion; the
conditions during and
after the snowfall are
the deciding criteria!
TEMPERATURE
Low temperatures and
warm air incidence exert
a massive influence
on the transformation
processes within the
snow cover, and thus
the avalanche situation.
WIND
Wind is the master
builder of an avalanche,
because it ensures
formation of snow slabs
through snow loads.
In this process particles
of snow are reduced
in size, loaded, and
deposited as cohesive
drift snow.
The stronger the wind,
the greater the accu-
mulation of drift snow.
ENGLISH
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