A v a l a n c h e

C o n t r o l ,

R e s c u e

a n d

E d u c a t i o n

• when theinstallationsarenotoperational,snowpack
  depthandstrengthreturnstovaluestypicalof
  snowpacks outside of the operational unit's influence.

Summary

Resultsfromthe1995and1996fieldworksupportour
previous findings (Elder and Newcomb,1994 and 1995) If
theobjectiveofusing GAZ-EXistoreduce the need for
artillery control, then spacing of the GAZ-EX installations
is critical formaximum effect in all types of layered snow
conditions. Locating GAZ-EX units too far apart may leave
areasofunstablesnowthatmayreleasenaturallywith
continued loading. If units are too close together, they may
not be cost effective.Because the initial cost of the GAZ-
EXinstallationishighrelativetoothermethodsofava-
lanche control,optimalplacementandnumberofunits
should be determined forthe maximum cost/benefit ratio
to be obtained.The opportunity to check the effect of no
control at one GAZ-EX site came in1995 when GAZ-EX 3
failed. Observations showed that the snowpack depth and
strength properties were significantlydifferent thantrends
seen atthe same anddifferentsites whenthe unitsarefunc-
tioningproperly.Localsnowdepthsweregreateras
expected based on increased preciptation,but ram resist-
anceshoweda larger increase thanwouldbe expectedfrom
the increased depth alone.

ACKNOWLEDGEMENTS

Robbie Fuller, Maria Newcomband Mark Newcombhelped
in the field. Ken SwedeenandSteve Kruse of the Wyoming

TransportationDepartmentgener ouslyprovided
information,photographs,and discussionregardingthe
GAZ-EX installations on Teton Pass.

REFERENCES

Elder,K.andR.Newcomb(1994)Fieldmeasurementsand
interpretationsofGAZ-EXinfluenceontheIntermountain
snowpack. International Snow Science Workshop, Snowbird,
Utah. p. 626-635.

Elder, K. and R. Newcomb (1995) The effect of GAZ-EX instal-
lations onthesnowpack,GloryBowl slidepath,Teton Pass,
Wyoming.The Avalanche Review , Vol. 13(4), American Asso-
ciationof Avalanche Professionals.p.1, 4-5.

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