ENVIRONMENTAL HAZARDS OF AVALANCHES: PRELIMINARY RESEARCH IN GLACIER NATIONAL PARK

Transcription

1 ENVIRONMENTAL HAZARDS OF AVALANCHES: PRELIMINARY RESEARCH IN GLACIER NATIONAL PARK Site Focus: Balu Pass, Glacier National Park, B.C. Avalanche path near Balu Pass. (Photo Courtesy of:

2 Research Question: What level of risk is associated with backcountry recreation in Glacier National Park, and should Parks Canada planning, zoning and decision making adjust to changes in the level of human related risk in avalanche areas? Phases in Research Process Field Work: Tree Core collection and analysis Climate Analysis: Correlating tree core and anecdotal evidence with climate parameters. Human Usage Analysis: Investigate zoning and planning policies for areas of high usage and high risk.

3 Researchers Ben Ferrel Keri Laughlin Kevin M c Phedran Mark Brown also thanks to Jim Gardner and Scott Jackson Tree coring in Connaught Valley. (Photo Courtesy of Jim Gardner)

4

5 Field Work: Tree core collection and Dendrochronological Analysis Data Collection: Target species: Subalpine Fir Sample population: Grizzly Mountain avalanche path, south slope of Connaught Valley. Sample design: Stratified random Analysis: Tree core measuring and observations in windendro software of scars and reaction wood to create spatial age classes. (Photos courtesy of : rtual_tour/how/treecoring.htm)

6 Number of Samples Number of Scars Date Range of Samples (Photo courtesy of Jim Gardner) Table 1: Summary of tree core data from Grizzly Mountain avalanche path. Balu Pass, BC Max age In range

7 Sampling Transect with observed age classes Transect of east side of path, day 1.

8

9

10 Avalanches in the Selkirk Mountains Avalanche near Roger's Pass. (Photo Courtesy of Environment Canada) Weather patterns in winter of resulted in an unstable snowpack in the mountain range surrounding Roger's Pass 2 fatalities occurred in separate events the bedding plane of both avalanches was on a layer of surface hoar the cause of the majority of human triggered slides in the Columbia Mountains (Jamieson, 2000)

11 Surface Hoar Extreme Surface Hoar in Alaska. (Photo Courtesy of: research.com/site/album.asp) same process as dew on a clear summer night develops during clear, cold weather spells, results in unstable layer when it becomes buried in the snowpack forms when air above snowpack becomes supersaturated in comparison to snowpack, water vapour condenses onto snow surface appearance of tiny "feathers on snow surface" Source: Daffern, 1999 Surface Hoar in the Selkirk Mountains. (Photo Courtesy of:

12 January 17th, 1988 Standfast Creek Avalanche location: east facing slope beneath tree line, Standfast Creek, approximately 20km SW of Mt. Fidelity in Glacier National Park heli ski group cold, clear weather (lows 12 o C to 21 o C) in the week prior, layer of surface hoar developed followed by heavy snowfall (123cm) in the days prior to the accident unstable conditions resulted size 2.5 avalanche triggered by leading guide one guide killed result of trauma injuries from being pushed into trees other factors avalanche released on convex roll in the slope slope incline=35 o Source: Jamieson and Geldsetzer, 1996

13 (Data courtesy of Environment Canada, 2007)

14 Avalanches in the Selkirk Mountains people killed in Avalanches in Canada 2003 the most fatalities in Canada since of these fatalities are the result of 2 avalanches in the Selkirk Mountains both avalanches were blamed on November Rain Crust Failure The mountains in the Balu Pass region, Rogers Pass, B.C. (Photo courtesy of:

15 Melt Freeze Crusts when wet layers on the snow surface freeze they form a slick bed surface (Jamieson, 2004) when the bed surface is buried, a trigger mechanism may cause the overlying snow to slide in a slab avalanche (Jamieson, 2004) 3 main types: Rain Crust, Sun Crust, Melt Freeze crust (Jamieson, 2004) weak bonding of snow above the crust is crucial to snow pack failure (McClung & Schaerer, 1993) Evaluating a crust in the snowpack (Photo courtesy of: large quantities of warm rain are required before melting at the snow surface occurs to form rain crusts that are significant instablities in a snow pack (Daffern, 1999)

16 (Data courtesy of Environment Canada, 2007)

17 (Data courtesy of Environment Canada, 2007)

18 Mount Cheops Balu Pass Avalanche February 1, 2003 Avalanche Path Location of Group Mount Cheops

19 Faceting weak faceted layers are caused by a temperature gradient in the snowpack (Jamieson, 2000) not only does a temperature gradient cause faceting, it prevents snow from rounding and stabilizing (Jamieson, 2000) Courtesy of : Faceted Snow Crystal photographed with polarized light (Photo Courtesy of: temperature gradients can be established by a warm snow surface buried by colder snow (Birkeland, 1998) temperature gradients can also be formed by short wave radiation warming deep snow on sunny days (south aspects), long wave radiation cooling surface snow on dry clear nights (Birkeland, 1998)

20 (Data courtesy of Environment Canada, 2007)

21 Bruins Pass Avalanche March 13, 1993 Avalanche Path Touring Route

22 Human Trends and Patterns of Avalanche Accidents Total annual fatalities have increased, per capita fatalities have decreased. This can be attributed to: a) Increased availability to information on avalanches. (e.g. bulletins from C.A.A. website) b) Enhanced public awareness. (e.g. Adventure Smart program) c) Enhancements in climate and weather technology, land zoning processes, as well improvements to safety and rescue protocol.

23 Trend and Patterns Month and Time of Day Highest numbers of deaths occur from January to March, when the snowfall levels are greatest in most mountain areas (Stubbings and MacDonald, 2000) Avalanche susceptibility tends to climax in the early afternoon between 12 2pm (Jamieson and Geldsetzer, 1996) Contributing factors are: 1) increased number of backcountry users on terrain during this time period, 2) warming of snow pack due to increases in air temperature between 12 2pm. Source: Jamieson and Geldsetzer, 1996

24 Types of Activity Source: Jamieson and Geldsetzer, 1996

25 Visitor and backcountry use Glacier National Park is growing in international recognition as a hub of backcountry touring. Steady and significant overall increase in winter use of the ACC huts in the Park (Glacier National Park shown in green bars) Source: Parks Canada, 2003.

26 Visitor and backcountry use the Balu Pass trailhead begins in the frontcountry Land Management Unit (LMU) of the Glacier National Park transportation corridor Parks Canada states in their Management Plan that this LMU is the busiest area in (Parks Canada s zoning system) Balu Pass is one of seven selfguiding trails extremely accessible for visitors. Balu pass is also considered a high use backcountry area the Balu Pass trail falls within the North Glacier LMU, stated as a wild, rugged area with old-growth forests where Visitors in most parts of the unit experience solitude, face challenges, undertake risks and must be self-reliant Source: Parks Canada, 2001 Source: Parks Canada, 2001

27 Highway traffic Increasing Vehicular Traffic through Glacier National Park, Trans-Canada Highway Vehicular Traffic through Glacier National Park, (Source: Parks Canada, 2001)

28 Future considerations Parks Canada should increase their collaborative work with other active avalanche bodies. - such as the C.A.A. and C.A.C. Develop co-ordinated backcountry user registration and permit systems Increased spatial analysis of avalanche activity and hazard zoning in national parks (Campbell et al, 2007) - use of Geographical Information Systems (GIS) Educate the general public on avalanche safety eg: the -Adventure Smart, a non profit education-based program initiated by BC Government -Rocky Mountain Sherpas film

29 References: