C a s e

H i s t o r i e s

ACKNOWLEDGMENTS

LiamFiztgeraldof Snowbird Ski Area foropinions on Provo
Canyon slidepaths.

Don Howlett of Alberta

Darwon Stoneman of Powderbirds Helicopters for timely ava-
lanche activityinformation.

Darce Trotter of Sundance Ski Area for avalanche control, his-
tory, weather data, etc.

UDOTRegion TwoAvalancheForecasters

Utah Avalanche Forecast Center staff for information and opin-
ions.

Photograph Melanie BuckUDOT Media Production Specialist
Bridal Veil Falls AvalanchePath

"Snow Avalanches in Provo Canyon"Published in ISSW Pro-
ceedings 1994 byKevin Griffith

BV US6S Highlight

lines.Trees were broken on the north side of the highway
fora widthof a400meters.Snow was deposited on the
uphillsideofthehighwayinadebrispile550meters
wide with the toe of the deposition 180 meters beyond the
highway.Thedeepest partofthedeposition wasacross
the Provo Riverfrom the slidepath on the county road. At
that point depth wasestimated to be 12 to 15 meters. There
were no reports of missing persons.
Theeventsdescribedabovebecomelessimpressive
when compared to the fact that the Bridal Veil avalanche
was roughly thirty percent of the avalanche that released
around 1 A.M. January 31. Fracture propagationalong the
summit ridge of Cascade mountain connectedthree sepa-
rate drainages, Bridal Veil, Bunnell Fork, and Big Springs.
In addition toBridal Veil, this massive slide ran the full
width of Bunnell Fork starting at3322 meters anddescend-
ing to 1920 meters.Fracture propagation continued hun-
dredsofmetersintoBigSprings,thedrainage southof
Bunnells. The crown facethat connectedthese three drain-
ages wasover three kilometers wide andaveragedbetween
twoandthree metersdeep. Thetotalarea involvedwas
approximately530 hectares. The alphaangleof the Bridal
Veil portion of the slide was calculatedto be 26º39'.
At the endof April theburiedrailroadcar wasstill under
avalanche debris.The roof started melting out at the end
of June and was halfway melted out by mid August.The
avalanchedebris on the county road had not melted when
this was written and the road was still closed.Several of
the conifir trees in the debris were approaching 300 years
in age. A conifirfrom a previous avalanche was over300
years old.

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