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

tion from 76% (forcoarse probing) to approximately 95%
(calculated forvertical probes hitting an area of 0.4 m² ).

SUMMARY

In avalanchesearch where time is criticalthe rescueleader
must focus available resources to achievethe highestprob-
ability of success.Weare taught to priorize the area of the
search to try to reach the victim more quickly. The exten-
sive historical data now available on burial depths permit
the rescue leader to consider focusing the search even fur-
therby limiting the depth of probing.Recent statistics in-
dicate that the majority of victims are buried within 2 m of
the surface and that the proportion of victimsfound alive
decreases withdepthofburialanddecreasesmarkedly
around 1.5 m.
It is ourproposal that if the rescue leader is faced with
probe-searching while liverecoveryisstillapossibility,
heshouldconsiderlimitingthedepth ofprobinginthe
interests of speeding the search.
Our field tests indicate that3-hole-per-step probing also
significantly improves the speed of searching. Setting up
the probe line for this technique is easy using finger-tip-to-
finger-tip spacing. The effectiveness of traditional coarse-
probing is dependenton a high degree of discipline of the
searchpartywheremaintainingcorr ectspacingis
important. However, with thethree-hole-per-steptechnique
described here, if the searchers happen to wander slightly
off line they will still be putting down a higher density of
holes than traditional coarse probing.
Withthe three hole per step technique, 2 probers cover
a width almost equal to 5 coarse probers. This deployment
mayhavethe added psychologicaleffect ofencouraging
small parties (self-rescue situations) toenergetically pur-
sue probing because the spacing ofthe probers doesnot
appear so hopelessly inadequate in comparison to the area
to be searched.

260

Some searchers and search leaders may already be em-
ploying these principals. These data andtests should sup-
ply a greater confidencein choosing to vary from the tradi-
tional techniques.

REFERENCES

McClung, D.M. and P.A. Schaerer. 1993. The Avalanche Hand-
book.The Mountaineers, Seattle,271pp.

Perla, R.I. 1967. Optimal probing for avalanche victims. USDA
Forest Service Miscellaneous Report 13.

Perla,R.I. andM.Martinelli,Jr., 1976. Avalanche Handbook,
U.S. Dept. of Agriculture, Agriculture Handbook 489, 238pp

Schild, M. 1963. Absuchen und Sondieren. Symposium über
DringlicheMassnahm enzurRettungv on
Lawinenverschütteten,Vanni Eigenmann Foundation,p.30-
32.

Schild,M.1974.Previous experience inthepracticeof ava-
lancherescue.AvalancheProtection,LocationandRescue.
Vanni EigenmannFoundation,p.51-75.

ACKNOWLEDGEMENTS

We wouldliketogratefullyacknowledgethegenerous
assistance of Knox Williams and Dale Atkins for providing
theU.S.data, Dr.Walter Goodand Hansjörg Etterofthe
Swiss Federal Institute for Snow and AvalancheResearch
forthe Swiss data, Dr. Ron Perla forhis help in obtaining
the rescuedataandfor his continuinginterestin avalanche
safety, andDr. Jürg SchweizerandPeterSchaerer for advice
and translations from German.
Special thankstothe probe teamwhoparticipated in
the field tests including: Allison Amero,Perry Davis, Jeff
Goodrich, DennisHerman, Jim Mammalis, Thea Mitchell,
MurrayPeterson,DaveRutherford,Percy Woods,Chris
Worobets,and toDave Skjönsberg and Gordon Peytofor
setting up the site at Roger's Pass.