Apologies for few updates, I’m finishing my Ph.D. thesis.

Gear thoughts from recent months: Microspikes are good, well made, grip well; BD Traverse poles (older model) are heavier, fold nicely, like ’em; BD Ion headlamp requires instruction-reading to install battery, is light, not super bright; 2014 BD Spot headlamp is bright, touch function is ~okay.

Skiing is good.

Allen & Mike’s Avalanche Book

We picked this book up at Powell’s in the autumn. I think my exclamation upon seeing it on the shelf was “No way! Allen and Mike have made an avalanche book!”


For those not familiar with Allen O’Bannon and Mike Clelland’s telemark and backcountry ski books, they’re informative and well-informed hand-illustrated guides to techniques and skills of use to everyone. All heartily recommended. This new book is up to date and down to earth. Snow science is described in functional detail, and the realities of avalanche terrain are shown in practical and visual detail. As with William Nealy’s “Kayak”, didactic cartoon diagrams can triumph over prose and photos.

For years, my singular recommendation for an introductory avalanche text has been Bruce Tremper’s “Staying Alive in Avalanche Terrain”. The quality of that text is timeless; it has a new companion. For new skiers without a scientific bent, or for younger backcountry travelers, “Avalanche Book” may be the more-effective book. A backcountry travel course with which I’m affiliated has chosen to try Allen and Mike’s book this year as the course avy text.

Another holiday gift recommendation from MeasuredMass. A look inside follows…

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The Snowflake (Libbrecht, Rasmussen)

A foray past the technical wing of Powell’s Books turned up a bunch of fun reading. Among them is this informative book on snowflakes.

IMG_0641Written by a physicist who developed a specialty in snowflake formation, and beautifully photographed. It’s a broad treatise on snow that’s accessible to everyone, from kids to graduate-level physicists. If you need a snow-focused holiday gift for someone who already has too many skis and bindings, this might be it.

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Voile Drifter 192 cm

After a fun demo of a pair of lightweight 120 mm skis at Vertfest, I’d kept an eye out for a sweet deal on a pair of truly fat skis.  The Drifter, at 153/128/141 mm, fits that bill.

These skis are used, but in stellar shape. The previous owner posted a review here. These skis are almost  certainly from Voile’s “zero-camber” sale of 09/10 skis.  Durability-wise, the previous owner claimed 70+ days; the bases are in stellar condition given that much use.


Weights: From the Wayback Machine in April 2010, the 192 claimed weight/ski was 2.11 kg/ski.  The skis weighed in at 2231 and 2217 g, yielding 2224±12 grams. That’s 5% high, even with binding holes drilled and some wear; perhaps pre-production weights were overoptimistic.

The ski dimensions are internally consistent at better than 100 microns, comparable to the amount of material removed by sharpening an edge. I haven’t yet made a major effort toward quantifying ski dimensions, but this is the best I’ve seen. Very nice work, Voile. Repeatability at that level hints at quality in other contexts. The ski topsheets claim 153/128/141 mm. My measurements give 155.1/127.3/141.3 mm, with uncertainties < 0.1 mm.  The ski shovel is so huge, it’s only barely measureable with a 6″ shop caliper!

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Black Diamond Drift 166 cm 2011/2012

A great deal on a pair of Drifts appeared on our local gear swap today, and I couldn’t pass it up. A friend’s pair of 165 cm Kilowatts is nearing the end of its service life, and the Drifts may be a partial replacement.

BlackDiamondDriftKilowattComparisonBy hand flex, the Drifts are far softer than the Kilowatts; we’ll have to see how they ski in a month or two. The tails are stiffer than the shovels, but they’re softer everywhere than the Kilowatts.

Weight-wise, the skis aren’t mint. The previous owner has drilled them once for Dynafits, and added tip/tail rescue holes. That said, these skis weighed exactly the same on my scale; we’ll call them 1464±1 grams.

I can’t find an official BD spec from the 11/12 season, ( claimed 1561 g/ski, which matches a blem spec at GearX. For the 12/13 model year (different graphics), the claim was 1432 g/ski.  These skis are very consistent in weight, and 6% lighter than the original spec, far more than can be explained by the drilled holes.

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Remembering David Pinegar

Reading through the 2012 ANAM, I came across Dave’s accident. Some things aren’t fair.

David’s Thesis. His work, and his work preceding the thesis, continues to have importance to the neutrino-mass world. The tritium and helium-3 mass difference measurements of which he was a part are timeless.

John Scurlock’s memorable sunset photograph, Scurlock’s note, Dave’s TR.

Dave on Chikamin.

He always did things his own way. I appreciate that now more than ever.

Almost-equal night

The Turn isn’t here yet, but it’s coming.


Carbon dioxide is stealing our oxygen

Our air is getting news coverage today, as the benchmark atmospheric carbon dioxide measurement at a spot in Hawaii has passed 400 parts per million, probably for the first (non-volcanic) time in at least hundreds of thousands of years.

400 ppm is an arbitrary benchmark, relevant to primates with ten fingers.  It’s still important; it’s the atmosphere we must breathe.

From plots like this, it’s clear that the carbon dioxide content of our atmosphere is rising. It is probable that the rising temperature of the globe, the loss of Arctic ice, and the melting of our precious glaciers is related to human activity. I’m a cautious scientist; I’d like to see this experiment played out with many Earths and many rises of civilization to be sure. If forced, I’d have to bet on the prevailing scientific view that human emissions are driving global warming.

That’s not what this post is about. The rise of ~100 ppm over the span of the plot above has an alternate interpretation. 100 ppm is 0.01% of the atmosphere. That’s not a lot. But, our atmosphere is only one fifth (20.946%) oxygen, so it’s an effect that’s at least five times larger. Our oxygen is being burned into stuff we cannot breathe. Continue reading