Parks / British
Columbia / Glacier
The combination of heavy snowfall
and steep terrain makes the area prone to avalanches.
The slide paths stretch from the tree line to
the valley floor. It is estimated that at least
20% of Glacier National Park is subject to avalanches,
with snow roaring down the mountains at speeds
up to 325 km/hour. Between 1885 and 1911, more
than 200 people lost their lives in avalanches
trying to maintain the railway line through
Rogers Pass. Unable to control the snow, the
CPR decided to avoid the pass and built the
Connaught Tunnel under Mt. Macdonald, bypassing
16 kilometres of the treacherous Rogers Pass.
When the Trans-Canada Highway
opened to the public in 1962, it too followed
the route through Rogers Pass, so avalanche
warning was a top priority. Elaborate snow sheds
cover some of the most dangerous sections of
road, but science and technology have given
us additional defences.
Glacier National Park is headquarters
for one of the most advanced avalanche monitoring
programmes in the world. The Avalanche Control
Group measures the snow pack and its volatility
and, if necessary, orders a controlled slide.
A special detachment of the Royal Canadian Horse
Artillery is directed to shoot an explosive
shell from a 105 mm Howitzer at the specified
target. There are more than 200 targets high
up in the mountains surrounding the Pass which
are used to trigger avalanches before they get
too big. A successful shot will cause the unstable
snow layers to shift, releasing an avalanche
safely, when the highway is closed.