I n s t r u m e n t s

a n d

M e t h o d s

benchedtestedandcalibrated. Thesensors werecalibrated,sensors were connected to the hardware via 50 meters of
so that a voltage would correspond to a specific angle ofcable.Sincethe sensors were installedin January thecable
tilt.Once seven corresponding angles were known in thewas laid on the snow surface.
x and y directions,and repeatability established,a linear
relationship is established to derive the remaining angles
of tilt.The linear equation derived forsensor #3 in the x-^{2.5 Data retrieval}
direction is:^{The data was downloaded from the dataloggervia RF te-}
lemetry every week for analysis.During a storm cycle data
y=0.0054x+0.1543Eq.(3)^{wasdownloadedandanalyzedmorefrequently.This}
where:^{allowed examination of snowpack strength andactivity on}
y=_voltage^{a real time basis.}
x=^{angle of tilt of sensor}_{3.PRELIMINARY RESULTS}

By knowing the voltage produced by the sensor, the an-^{The preliminary results obtained from the creepand glide}
gle of tilt of the sensor is derived from Eq. (3).For each of^{sensors showed promise.The majorproblem was the in-}
the three sensors a linear equation was derived in both the^{stallation and operation of the sensors.Since the sensors}
x and y direction.^{became operational in late January, sensors #1 and 2 were}
buried under 2.5 meters of snow.Sensor #3 was the only
2.4 Instrumentation^{workingsensoronce thesystemwasoperational.Two}
Once the C&G sensors are in placein the starting zone, the^{important results were obtained from the data.The elastic}
data collectionstation was installed.The station consisted^{response of the snowpack to explosives and the increase}
ofadatalogger,multiplexerand 12voltdcsolarpower^{in creep rates due to loading were recorded that preceded}
supply.Thestation anddatais accessedby radiotelemetry.^{widespread avalanching.}
A solarpanel was pointed at 25 degrees aspect due to the^{On February 20, 1996 an explosive charge(2kg / PETN)}
terrain and tiltedslightlytowardthe ground sothatthe^{tiedtoabamboopolewasdetonated 1meterabovethe}
energy from the snow reflectivitywould chargethe battery.^{newsnowsurfacetocreate anairblastinHarold'sslide}
AprogramwasdownloadedtothedataloggerviaRF^{path at 1200 hours.The elastic response of the snowpack}
telemetry to monitorthe sensors every 15 seconds.Also,^{due to the explosive charge was capturedby the C&G sen-}
capabilities at the site allow for real time monitoring.The^{sors.Thisisevidentwithanincreaseincreep rateor}
programretrieved themaximum and minimum angles and^{deflection of the sensor.This rapid increase was followed}
calculated the averageovera fifteen minute interval.The^{by a slow stabilization of the snow.This is evident by the}
angle of the sensormoving back toward normal.In start-

Figure 1. Probe #1 r eflecting no creep movement.

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