Gear of the Week | PoleClinometer and Clinopole

The slope gradient is an essential component in the risk assessment of slab avalanches. SnowCard, Avaluator, graphic reduction method and also topographical methods such as Ski Touring Guru and avalanche terrain classifications are mainly based on the steepness of the terrain. Experienced freeriders can estimate the relevant gradient classes (<30°, 30°-35°, >35°) quite well in the terrain, but a regular ground-truth never harms anyone.

PoleClinometer

The PoleClinometer is a sticker that places bearing lines on the pole at certain degree intervals. These enable "line-of-sight inclinometry", i.e. you dangle the pole and take a bearing either parallel to the slope, up the slope or down the slope. The best way to understand how it works is to watch the info video on their website. The slogan "in any case, just Dangle It!" definitely says it all.

I think it's a great tool: It's simple, doesn't cost much, weighs nothing and allows you to determine the slope inclination in different scenarios. However, depending on the type of grip/design of the pole, it may dangle at a slight angle, which in combination with the shape of the slope can make it difficult to find a precise bearing line. I estimate the accuracy of this non-contact slope inclination measurement to be around +/- 2°. The biggest problem, however, is the wind - and a buyer review sums it up perfectly:

"Great idea, but in practice the stick moves far too much even in light winds to focus on the fine lines and get an accurate measurement ... In this case 'approximately' is just not good enough"

gear of the week

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Dangling the slope gradient with the PoleClinometer: slightly over 30°.

Anselm Köhler

Clinopole

The second tool is a contact inclinometer for determining the inclination of the terrain at the place where you are currently standing. The pole with the inclination scale is inserted vertically into the snow and the second pole is placed horizontally against the white marker to read the slope inclination. In principle, it is similar to using the poles as an equilateral triangle - see the good article from the Alpine Club. However, with the Clinopole you can directly read off the slope inclination and don't have to remember what 10 cm further from the grip distance means in degrees.

How exactly to use the Clinopole method is described on the exhaustive website. However, I find the website too detailed, which makes the simple method confusing. But if the tool catches on, then the instructions can also be improved.

In addition to the gradient scale, the colours of the avalanche danger level (yellow=2, orange=3 and red=4) are also printed. This allows you to see at a glance whether you are already "too steep" for the current danger level.

In practice, the system works well and once you get a hang of it, the slope can be determined in under 15 seconds. The inclination scale suggests that you can measure to the nearest degree, but there is an uncertainty of +/-2°, just as it feels, whether the poles are placed in the snow up to the snow disc or only up to the tip. The poles must also be held exactly vertically and horizontally along the fall line of the slope. The horizontal pole is not so problematic thanks to the spirit level, but the vertical one requires precise "dangling", which in turn tends to be susceptible to wind.

The Clinopole system determines the slope gradient on site. Depending on how soft the snow is, the vertical pole sinks further and causes a measurement inaccuracy. Here the reading is 38°, and in reality it is 2-3° less. Yellow scale range means that the slope gradient is basically OK for moderate avalanche danger (lvl 2).

Anselm Köhler

What science says

The PoleClinometer and Clinopole system was presented at last year's international snow science workshop in Tromso (ISSW 2024), together with a publication that investigated its accuracy and handling. The publication as part of the poster "Is slope perception biased?" can be found here.

One result is that, depending on the level of experience, the slope inclination is underestimated by experienced riders and overestimated by inexperienced riders. So there seems to be a certain bias for every freerider, and everyone can benefit from regular measurements. The second result is that the stickers for the poles work well and therefore coincides with my experience. With a little practice, the participants learnt to estimate the slope inclination 50 % better and were also able to significantly reduce the time needed for measurement.

Finally, respondents were asked about their satisfaction with the Clinopoles. Opinions were mixed: while some found the handling cumbersome and potentially inaccurate, others praised the ease of use for contact measurements. Four people found the device easy to use overall, and one person emphasised the positive effect on avalanche risk awareness. Overall, the majority of participants were satisfied and will use the Clinopole again next season.

Win your Clinopole

You can win a sticker set consisting of a PoleClinometer and ClinoPole. All you have to do is share your experience with measuring / estimating slope inclination or even misjudging. Write this in the comments below or in the social media post that appears (PowderGuide@Instagram / PowderGuide@Facebook) and the winner will be announced by March 2nd.