Asulkan Valley Avalanche track Geography 477 Fall 2007 Penny Simpson, Jessica Paramio, Maciej Stetkiewicz, Ashley Dittmer
RationaleRationale Objectives Background Methodology ResultsResults Discussion Conclusion Recommendations Outline
Rationale Highly Highly used trail that showed evidence of frequent high magnitude avalanches. Areas Areas is frequented in the winter and early spring by cross country skiers
Objective Determine frequency and distribution patterns of high magnitude avalanches on recreational trail. Analyze Analyze present data accounts of trail usage.
Site description Located directly off of Highway 1 in Glacier National Park. Base of trail is located at Illecillewaet campground. Asulkan trail is 6.5 km long. Study site was approx. 3 km into trail. Max avalanche path crosses trail approx. 375 m.
http://webmaps.gov.bc.ca/imfx/imf.jsp?site=imapbc
Team Avalanche, Missing Boot Brook and our Avalanche shoot
East and West viewpoints
Subalpine fir age range 3-4003 yrs Western Western Mountain Hemlock age range 7-8007 yrs Englemann Spruce age range 4-5004 yrs Tree species
Tree coring Base cores taken from the ground Scars
Scars
Methodology Took base core samples and scar samples. Scars were taken wherever they could be found at various elevations. A transect was set up on the northern side to produce age profile. Took tape measurements of estimated transect avalanche and distance traveled up slope, slope measurements. Sanded samples using six different grades (50, 80, 120, 220, 400 and 600). Scanned and analyzed samples with WinDendro 05/06 and Microscope.
Close relation between curves - Tree age useful as avalanche indicator.
Change in tree age with distance towards the interior of the Avalanche shoot. Decrease in age with the exception.
Assume Assume avalanches are controlling factor on tree age Scar Scar and tree age data to determine the minimum number of avalanches over a period (1933 - date of oldest found event). Frequency and magnitude - number of events and extent of avalanche
Avalanches that reach the lateral extent of the shoot occur less frequently The The exception in the age prolie is a bit of a puzzle - maybe indication of different avalanche paths Additional research required
25 events with magnitude sufficient to reach Asulkan trail - about every 4 years 3 3 events with magnitude sufficient to climb about 100 m up the opposite slope - about every 37 years 1 1 event with magnitude sufficient to climb 150m or more up opposite slope - about every 73 years
Risk is subjective
Asulkan Risks http://www.pep.bc.ca/hazard_preparedness/pcan_terrain.pdf
Park usage From From 1991-2001 traffic increased 1% to 2% annually Ski tourism increasingly popular By 2001 Asulkan trail head exceeds capacity Asulkan Asulkan classified as a High Use Backcounty Land Management Unit http://www.pc.gc.ca/docs/v-g/bc/glacier/pd-mp/toc-tdm_e.asp
Trail Usage winter season
Monthly usage
Conclusions Evidence Evidence that high magnitude avalanches do cross the trail frequently There There is a risk to cross country skiers Further Further research is needed
What we would do differently More cores from both sides. Difficulty in identifying trees and types of scars (fire/bear/avalanche). Coring issues, and finding scars. Problems with project: absence of trees does not mean it is because of avalanche- heavy snow pack. Judgment call in approximate length of max. avalanche track. Put shoe in bag to cross river
References imap BC http://webmaps.gov.bc.ca/imfx/imf.jsp?site=imapbc Avalanche Terrain Ratings for the Mountain National Parks, Parks Canada http://www.pep.bc.ca/hazard_preparedness/pcan_terrain.pdf Parks Canada trail count data courtesy of Anna Brown, Park Warden Parks Canada, Mount Revelstoke National Park of Canada and Glacier National Park of Canada and Rogers Pass National Historic Site of Canada Management Plan, http://www.pc.gc.ca/docs/v-g/bc/glacier/pd g/bc/glacier/pd-mp/toc-tdm_e.asptdm_e.asp