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Re: TRAINS article on Cascade Tunnel
Author: Bruce Kelly
Date: 12-22-2009 - 12:35
This subject was discussed at length over on trainsmag.com.
As Steve Carter points out, the author's proposed route along predominantly north-facing slopes would indeed have several avalanche problems. Thirteen documented avalanche chutes just between Scenic and the west portal of the old Cascade Tunnel. Half of these are rated "high" to "frequent" for avalanche potential.
The author blames sunshine directly striking south-facing peaks for the avalanche danger on Stevens. All of the exhaustive studies I have read on northern Cascades and northern Rockies avalanches have pegged the primary cause to be heavy snowfall followed by rain and/or sudden warming. This results in a heavy, unstable slab which eventually breaks free, especially if resting on prior layers of condensed ice or snow. A north-facing slope does not automatically minimize avalanche potential. Just read up on the history of winter disasters on CP's Field Hill.
As Steve Carter points out, the author's proposed route along predominantly north-facing slopes would indeed have several avalanche problems. Thirteen documented avalanche chutes just between Scenic and the west portal of the old Cascade Tunnel. Half of these are rated "high" to "frequent" for avalanche potential.
The author blames sunshine directly striking south-facing peaks for the avalanche danger on Stevens. All of the exhaustive studies I have read on northern Cascades and northern Rockies avalanches have pegged the primary cause to be heavy snowfall followed by rain and/or sudden warming. This results in a heavy, unstable slab which eventually breaks free, especially if resting on prior layers of condensed ice or snow. A north-facing slope does not automatically minimize avalanche potential. Just read up on the history of winter disasters on CP's Field Hill.
