Avalanche Initiation & Snow Mechanics – Continued Professional Development IFMGA

This week we have had the first winter snowfalls here in the Alps and I got the chance to meet up with Alain Duclos once again to discuss his favourite topics of snow mechanics and in particular crack initiation, weak layer collapse and crack propagation. It’s kinda comparable to my work as an engineer and fracture mechanics in weld and acceptable flaw size that wouldn’t result in weld failure for the design load.

Alain is an avalanche expert, responsible for road safety in the Haute Maurienne which is home to the Frejus Tunnel – a major freight and transportation link between France and Italy that is over looked by some impressive alpine terrain. Sadly, Alain is often called as an expert witness for avalanche accidents in the Alps.

survivors are generally surprised that the slope avalanched and often underestimate the slope angle.

This highlights 2 things. The ability to accurately gauge a slope angle, remembering anything above 30 degrees puts you in avalanche terrain while also considering overhead terrain & the fact that they were surprised means they were operating in a relaxed mode, perhaps due to failing to recognise they were in avalanche terrain or failure to assess the risk. Alain’s website data-avalanche is a ‘go to’ teaching, training, and reference resource for everyone to use.

There are 6 main criteria to review and assess for avalanche danger; the avalanche bulletin, slope angles >30º, recent avalanche observations, rising temperature & thawing, overloading due to wind accumulation / new snow / rain, and the possibility of a buried weak layer which a bulletin should highlight for well frequented areas.

There are 4 vigilance modes, relaxed, suspicious/cautious, alert & risk or gambling mode. It is clear that if you are relaxed and get caught in an avalanche, then there has been a failure in the observations made.

Play long enough in gambling mode and the statistics will catch up with you. However to complicate the matter further, Humans fall into 4 different categories for decision making traits, and at best only 2 of these types of people are likely to make conservative stand alone decisions (ref Powder magazine’s – The Human Factor 2.0).

Extract from Powder mag’s The Human Factor 2.0

To set the scene we were on the mountain after the first 30 cm snowfall of winter. The Alps has another hot summer and then a cold snap at the end of September brought around 1.5 m of snow and was followed by nearly 2 months of Indian Summer. Meteo France had not started avalanche forecasting and so digging a number of snow pits would provide valuable current information on snowpack stability. 

Usually I would have been skiing since September but with the new norms this was my first day on snow. We did a number of investigative snow tests between 2750 m and 2350 m on northerly aspects on 30-35 degree slopes. At each site 2 Compression Tests (CT) and a Propagation Saw Test (PST) were performed. For the first time all the tests yielded similar results – a weak layer lying just below the crust of the old snow surface yielding crack initiation, propagation and failure. Skinning around on the flat yielded a number of whoomps indicating collapse/failure of the weak layer. Its early days yet and no avalanche control has been done yet but it was definitely interesting to see whats going on right now.

Preparing the extended site for 2 Compressions Tests and Propagation Saw Test – circa 2.5 m long worksite
Compression Test 30 x 30 cm isolated column
Failure with Propagation Saw Test

I run 1 day avalanche awareness courses throughout the winter so don’t hesitate to contact me at rosshewittguiding@yahoo.com or phone/WhatsApp +33781287608 If you want to expand your knowledge and safety margins this winter.

The Best Runs of 2020

The best ski runs from 2020. We started the season down under. New Zealand must be one of my alternative spiritual homes, a place I’ve visited several times and feel completely at home. For skiing it’s like my Super Bowl. You may make all the moves and just be out of luck with high winds making you question the sanity of opening the outside door. But make the finals and on ‘The Day’ NZ will show you her magic and allow you play your A game. With @davejsearle we added a 700 m line to the Caroline Face, skied the 2nd known descent of Bowie Couloir and did another lap on the East Face of Cook. Back in Chamonix just as the season got good lockdown came and we had a wait of 2 months confined to our homes before restarting the season with a run on the Midi North Face to start the high mountain season. Dreaming of skiing during lockdown 2, hopefully it will be over soon.

Skiing Col de la Brenva

Spring 2020 in France was a strict 2 month lockdown due to the Coronavirus pandemic. I didn’t see a soul for 55 days except for the gendarmes policing the lockdown outside my house, freely handing out fines to the unfortunates for minor misdemeanours. As soon as lock down lifted I went back to my spiritual home in the mountains with my friends and skied the North Face of Aiguille du Midi. What joy to be back skiing after a 2 month hiatus. The post lock down season would be a short one for me with the lift only open at the weekends and a massive project on a scale that was hard to comprehend drawing all my energy. However we made some nice days, Tacul, Gervasutti Couloir, Contamine Negri, and Col de la Brenva to finish the season. Soft spring snow made for relaxed skiing and some cloud in the Brenva Cirque made everything feel very atmospheric, oh an a massive rimaye at the bottom made for an exciting exit onto the debris cone. The slog back up the Valley Blanche in desert heat wasn’t so fun but the bars were open that night for the first time and the cold beer never tasted so good.

Rating: 1 out of 5.

Unlocked Ski Aiguille du Midi North Face

France has had one of the strictest lockdowns in Europe behind Italy and Spain so after 8 weeks of not seeing a soul it was great to return to Aiguille du Midi with friends and make that big turn left down the North Face.

Max Ritter of Teton Gravity Research writes:

This weekend marked the re-opening of perhaps the most iconic ski lift in the world: the Aiguille du Midi’s Telepherique in Chamonix, France. Home to unquestionably the gnarliest lift-access terrain in the world, the Midi was closed for most of its prime spring season, leaving local skiers and riders frothing to get back up into the icy heights of the Mont Blanc Massif as soon as possible. Their prayers were answered this past weekend.

RELATED: Check Out Vol. 1 Of the TGR Journal

None other than steep skiing mastermind Tof Henry and a group of friends made it up there early and skied some classic lines that look like they’re actually still in really good shape for the end of May. Check out what Tof and local IFMGA guide Ross Hewitt got into on their first day back on skis after the COVID-19 lockdown.

 

Skyway Forever

Seems like ages since we got to ski endless 1200 m runs but finally its showing signs in select places of getting good in the Alps and today I sneaked a few runs in there before the storm arrived with my good buddy and Black Crows team mate Tom Grant. Here is a photo he took of me sneaking between the hanging glacier and the rock using the features to provide some slope definition as the light flatted out.

Ross glacier