I n s t r u m e n t s

a n d

M e t h o d s

Remote

Avalanche

Warning-,

Alarm-

andControlSystems,

andExperience

Fundamentals,

Applications

Hansueli

Gubl er

AlpuG, Richtstattweg 2, CH 7270 Davos Platz, Switzerland

Tel.&Fax. (41)-0-814161019, e-mail: gubler@vaw.ethz.ch

ABSTRACT

Today,temporarymeasurestoimproveavalanche safety
often depend on remote measurements by automatic sta-
tions.Thesnowprofileradarallows fordirect measure-
ments of snow accumulation, settling, fracture height and
water percolationwithin avalanche releasezones.Alarm
stations automatically recognize avalancheflow and close
traffic lines. Remote control of GAZ-EX exploders supple-
mentedwith improvedsystemchecks,profileradar and
seismometerreduce the residual risk foravalanche acci-
dentsbyapplying themethodofartificialavalanche re-
lease.All systemsare based on identical technology and
can be inferred from control- roomcomputers having the
necessarysoftwareincludingaccess andsecuritycodes
installed.

INTRODUCTION

Temporarymeasurestoimproveavalanchesafetygain
importance.They quite often offerimproved benefit/cost
ratios at comparable residual risk. Their applicationis lim-
ited tothe protection oftraffic lines,skiareas and other
zones thatcanbe closedandevacuatedany time, andwhere
structures aredesigned to withstand avalancheforces. On
theotherhandtheimpact onthecountrysideismuch

smaller using temporary methods compared to permanent
structures as barricades, dams orgalleries.
Toconfigure alarm-, warning- andcontrol-systems,the
physics ofavalanche formation and avalanche dynamics
have to be well understood.Considering this knowledge,
ithastobe decided whatkind ofparametershave tobe
measured. We have designed a new generation of sensors
and measuringplatforms:a redesignedsnow profile radar
capable to measure snow accumulation, settling, layering,
surfacemelt andwater percolationas wellas fracturedepth,
aninfraredthermometertoaccuratelymeasuresnow
surfacetemperatureandloggersoftwarethatimproves
accuracyof snow heightmeasurements, determines quality
numbers for the measured parameters and directly indexes
the actualstateof the snowsurface.Thereforethe formation
of weak layers as one of the necessary conditions forslab
avalanche formationisindicatedbythesystemwithout
the necessityof any centralcomputing.Avalanchecontrol
systemscombinelocalremotemeasurementswiththe
control ofone orseveral GAZ-EX-cannons.The GAZ-EX
control itself has also beenimproved by directlymeasuring
pressuredropsduringinitialization,groundtrembles
caused by the detonationand byperforming continuous
systemtests.The geophones alsomeasure and indicate

Fig. 1.

regional base stations.

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