​Introduction

 

Located in Garibaldi Provincial Park next to Whistler, BC, The Spearhead Traverse is one North America's most popular ski traverses. The traverse can be done in a day but the 30-40km route usually takes two. ​There is currently a plan in motion to put three new huts along the Spearhead Traverse. The huts would allow travellers who plan to do the traverse over multiple days to cook and sleep under shelter instead of in a tent. These huts are likely to make the trip even more popular than it already is, bringing lots of skiers to the traverse who have never been before. This project aims to serve as a guide for the hut-to-hut trip by proposing a safe, efficient, and fun route from Whistler Blackcomb Resort / Garibaldi Provincial Park boundary, connecting all the huts along the entire Spearhead Range to the other side. The route was decided based on the criteria of avalanche danger, landcover, and the direction of the slopes of the terrain.

Avalanche Danger

Avalanches pose a very serious danger for anyone who ventures into backcountry mountains. The Canadian Avalanche Association was the primary guide for all information regarding avalanches used in this analysis. From their information I concluded that slope angles and landcover were the two most critical considerations in avalanche danger that remain relatively stable over time. From their website I gathered that certain ranges of slope angles are recognized as either inhibiting or promoting different types of avalanches. 0 - 25° slopes rarely experience significant avalanches, 25 - 45° can have frequent and deadly avalanches, and +45° slopes have the most frequent but least intense avalanches. Different types of landcover can also promote or inhibit avalanches. Generally speaking, dense trees act to anchor the snowpack and prevent it from sliding, while open snow is the most vulnerable to slide. Both of slope angle and landcover were considered in a multi-criteria evaluation to assess the entire Spearhead Range for avalanche danger risks. It is important to note that there are other very important factors to consider when discussing avalanche hazard in the backcountry, but they are difficult to address using GIS. This project does not consider the added complexities of the characteristics of the snowpack, seasonal or local weather, and the characteristics and experience of the user. 

Satellite image of of the Spearhead Range taken from Google Earth with the general route of the Spearhead Traverse drawn on in red.

Landcover

Separate from its role in avalanche danger, landcover influences the travelling speed of a party on the traverse. Open snow is the easiest surface to travel on because there are no obstacles to navigate around, while a dense forest can take considerably more time and effort to navigate through. The landcover data used in this project described the Spearhead Range during the summer and thus had several landcover classes that do not exist in the winter once snow has accumulated in the alpine elevations. For this reason the landcover categories herb, shrub, grassland, waterbody (lake river), wetland, and open terrain, that appeared above the tree line were all converted to being snow. 

Terrain

Terrain is an important consideration when analyzing the traverse because the mountainous terrain of the Spearhead Range can be quite jagged and certain features are almost certainly impossible for travellers to cross. It is also important to remember that this trip is primarily a skiing trip and so I wanted to include some downward slopes for which to ski. Steep slopes are more difficult to ascend than shallow ones, and both require more energy than travelling across flat ground. On the other hand, travelling down a slope is easier and faster than travelling on flat ground. In this project I decided that 60° slopes were too difficult to ascend and would be considered nearly impossible in the data analyses. I also chose 60° as being the steepest slope that someone would likely ski down. This is assumption won't be correct for all skiers as a 60° slope is fairly intense to ski down, but when terrain and avalanche danger were considered together it was rare that a 60° slope was considered the best route.