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AASI Instructor
Join Date: Aug 2007
Location: Mt. Hood Oregon
Posts: 3,360
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Mt. Hood Meadows Getting a Howitzer for Avalanche Control
Much of the best terrain that Mt. Hood Meadows has to offer is not seen from the main area. We have an extensive "inbounds backcountry" and frequently our intense snowfall and steep pitch keeps this gem off limits. With huge, wind loaded open slopes in excess of 40 degrees and thousands of vertical feet, we have had some slides of almost biblical proportions in this area. Mt. Hood Meadows is in the final stages of the approval process to secure a Howitzer to better trigger controlled slides which should help keep this great terrain open more often, This year with record amounts of snow, Superbowl has rarely been open and with the season end fast approaching with no end in sight of our winterlike conditions, access to this expert only terrain looks to be short lived. The massive slides that occur in this area are an almost garunteed fatality to anyone caught in one regardless of equipment; being hit by hundreds of tons of fast moving, heavy wet snow reduces survivability rates to absolute zero. Yet, every year, passes get pulled from people who remain totally clueless of avalanche danger. While this may be Darwin in action, the real problem is the risk it puts the ski patrollers and other responders in. Hopefully, this new system will make access much more reliable!
From Matt`s Blog:
Avalanche Control - A New Approach - MATT'S BLOG
Quote:
Avalanche Control - A New Approach
Hi folks.
For the past year, Mt. Hood Meadows has conducted extensive research on developing an improved avalanche control (AC) program that will provide for the safety of our employees conducting avalanche control, and to better serve skiers by getting our in bounds terrain – in particular Heather and Clark Canyons – open more frequently and routinely after storm cycles. This blog is a continuation of prior blogs addressing snow safety at Mt. Hood Meadows and is intended to:
• Review our in bounds terrain and the associated avalanche threats,
• Inform about current options to mitigate this threat, including current procedures,.
• Present the option we are most likely to pursue and the approvals process required for implementation,
The Terrain
The terrain in Heather and Clark Canyons is big, varied (convex slopes, rock cliffs, steeps, trees, etc.) and uniquely spectacular. Combine this terrain with an ample supply of northwest snowfall and you have the recipe for some incredible skiing, snowboarding, and avalanches. Mitigating avalanche hazards in this varied terrain is challenging, particularly during storm systems. It’s hard to get to -- the Cascade Express chairlift is frequently crippled by a large volume of rime ice and it can’t run early, if at all.
Snowmobiles and snowcats are ineffective in pulling the patrollers uphill through deep snow and whiteout conditions, so patrollers must climb on skis or wade uphill with heavy packs of explosives to reach their control objectives. Under such conditions, more patrollers performing snow safety work is not the answer. In fact, such a strategy would further compound safety and productivity challenges in this area.
Our current avalanche control program is one that we have used effectively, for many years and includes a series of both passive and active measures. Passive methods include avoidance and closure. While there are areas within our permit area which we avoid altogether, we use gated ropelines to manage our avalanche closures, as the map below indicates.
Unfortunately, temporary closures are only respected if they are infrequent and of short duration. Long delays in opening Heather Canyon after a storm cycle frequently lead to closure violations. The threat of lost skiing privileges, a fine or possibly death if overtaken by an avalanche, apparently are insufficient deterrents. Safety of our employees and the public is the primary concern of Mt. Hood Meadows Ski Resort and the Mt. Hood National Forest.
Control Zones are often used to help define the terrain in avalanche control programs. Typically, multiple avalanche paths grouped within one zone may have similar terrain features, similar weather patterns, and require similar hazard reduction measures. You can see the different zones on the map below. Each zone generally requires its own unique approach and technique.
Mt. Hood Meadows ski patrol routinely provides active control measures into these areas, including the use of:
• Compaction – Primarily skier compaction, which works best in Lower Heather Canyon, but must thoroughly disturb every snow layer in order for skier/rider compaction to be effective
• Ski Cutting – A major staple of most ski patrol control teams, but is not suitable for hard or deep slabs on the unconfined convex slopes that prevail in Heather & Clark Canyons,
Deep slabs are possible as shown here in A-zone, beneath the Basalt Cliffs
-- you definitely wouldn’t want to try ski cutting this slab.
• Explosives – Using hand charges is the most common method of Avalanche Control delivery in use at Meadows today. Individual explosive charges weighing from two to ten pounds each are thrown, suspended or placed onto the avalanche path by our control teams.
Despite the inherent and obvious hazards associated with handling explosives, using them can reduce control team members exposure to avalanche hazard.
The sequence below shows the effective use of hand explosives to release a slide in A-zone.
We also use an avalauncher which uses compressed nitrogen to throw a 2.6 pound explosive charge designed to explode on impact. Avalaunchers are often times not effective during storm periods as the light-weight charge can be blown off course. And during storm conditions visual confirmation is not possible to determine whether avalauncher “shots” have been effective.
Here’s one of the key challenges of avalanche control work in Heather and Clark Canyons: Because they both funnel into Lower Heather Canyon all of these zones have to be controlled before the terrain below them can be opened. Our crews have to blast their way from one zone to the next, first controlling the Basalt Cliffs, then Upper Heather ridge, on to Clark Ridge and down to Accordion Bowl.
This also means that all the explosives for this trek must be carried in, so our patrollers are performing this work wearing 70 and 80 pound backpacks filled with explosives. Meanwhile, other teams are controlling Heather Ridge, Clark Canyon and Jacks Woods.
The lower canyon can only be opened once the upper potential avalanche areas have been controlled.
Control teams that climb the ridge to reach the upper Basalt starting zones are faced with a very big challenge. These starting zones are huge unconfined convex rolls that get steeper the farther out you go. These are some of the most dangerous types of slopes for control teams to be on. Control teams here are also frequently hampered by high winds and poor visibility. The snow surface is often wind packed and very firm which requires the hand charges to be tethered to keep them from rolling down the slope. “Tippy-toeing” out onto a huge convex hard slab, in a “whiteout”, to tether a five pound booster to your ski pole is extremely dangerous. There is rarely a safe route, and there is no place to hide.
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Mt. Hood Meadows Getting a Howitzer for Avalanche Control
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