A v a l a n c h e

D y n a m i c s

a n d

D e f e n ce

at different rates,there is the possibilityforcomparison.
Intuitively one wouldexpectthat thedrier anddeeperslide
would have a lowerS/N ratioallowing ittotravel faster
and further. Improvements to measurements of both the S/
Nratioand the slidedepth can beobtained byinsuring
thatthe slideencountersnoobstructionsdown slopeof
the plate limiting deposition tothat caused byfrictional
deceleration only.
In the future it may be possible to calculate the rate of
deposition from velocity sensors along with density meas-
urements and subtract itsnormal and shearcomponents
fromthoserecorded bythe shearplate toobtainamore
accurate measurement.
With alloftheinstrumentation inplace and working
correlation between the slide parameters can be made al-
lowing fora plot of the S/N ratio against the velocity nor-
malized by the densityand normal shear stress.This curve
should give tremendous insight tothe dynamics and the
relationshipoftheflowparameterswithinactualava-
lanches, hopefully leading to a better model for determin-
ing runout distances.

CONCLUSIONS

The increased flow distances of dry snow avalanches ap-
pears to be connected with the lower S/N ratios that result
at the slide's base.

REFERENCES

Dent,J.D. "TheDynamic Friction Characteristic of a Rapidly
ShearedGranularMaterialAppliedtotheMotionofSnow
Avalanches",Annals of Glaciology,Vol. 18, 1994.

Dent,Adams,Bailey,Jazbutis,andSchmidt,"Velocityand
MassTransportMeasurementsinaSnowAvalanche",Pro-
ceedings of the International Snow ScienceWorkshop 1994.

Louge,Steiner,Keast,Decker,Dent,andSchneebeli,"Appli-
cation of Capacitance Instrumentation to the Measurement of
Density and Velocity of Flowing Snow", accepted for publica-
tionCold Regions Science and Technology.

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