I n s t r u m e n t s

a n d

M e t h o d s

ingzones adjacent toHarold'sslidepath,controlroutes
reportedthe same results.All avalanche activity was con-
fined to the new snow within the ski resorts boundaries.
On February 22, 1996, during a significant storm event,
the precipitationintensity increasedandwidespreadnatu-
ralsnowavalanchingoccurred.Duringthisperiodan
avalanche releasedfrom White Pine #3 and crossed High-
way 210.White Pine #3 starting zone is located at an el-
evation of 3,000 meters with a slope aspect of 90 degrees
and a slope steepness of 37 degrees.This avalanchepath
is located 2,560 meters fromthe C&Gsensors.The C&G
sensors during this period of increasedactivity, indicted a
rapidincreasein creeprates.Thecreeprate spikedat about
the time White Pine #3 crossed the highway.
In April sensor #3 was excavatedand examined. RECCO
Avalanche Rescue Reflectors were attachedto the sensors
priortofield installation.These reflectors were used to
locatethesensors.Sensor#3wasfoundparalleltothe
slope.The force of the gliding snow bent the ready rod to
andangleof40degrees.Thecoaxialsteelspringwas
damaged.Oncethe pressurearoundthereadyrodand
sensorwere releasedthe steel spring was bent at an angle
of 15degrees.Also,the tension in the wiring caused by
the gliding snow created a downslope force on the sensor
and readyrod.This tensioncontributedto a moment about
the sensor and ready rod.

DISCUSSIONAND CONCLUSION

4.1 Storm Data

The data presented represents significant highlights dur-
ing thewinter of 1995-1996.The winter of 1995-1996 began
slowly with no significant snowfall till after the first of the
year.The sensors were not operational tillafterthe first
two significant stormcycles.At this time,the snowpack
at Harold's slidepathwas 200 cm in depth. This completely
buried sensors # 1 and 2 and left sensor#3 able to record
surface movements in the snowpack.There was no deep
slab avalanche in the slidepath after installation.
Theeighth stormoftheyeararrivedonFebruary19,
1996.Between 0400 hours on February 19 and 0400 Feb-
ruary 20 the Collins snow studyplot at anelevationof 2,990
meters had received53 cm of snow with 5.91 cm of water
(11% density).The winds were from the Northwest at 51
km/hr.During this storm cycle the tilt sensors were moni-
tored.

4.2 Sensor DataResultsand Discussion

Sensors #1and 2 indicated little tono movement in the
snowpack.It is believed that those sensors were deflected
beyond the 90 degreerangeand wereparallel to the slope.
This extreme deflection would cause anymovement of the
snowtocreeporglideoverthesensors.Therefore,no

Figure 2. Probe #2 r eflecting no creep movement.

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