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International, independent, e-magazine on skydiving, BASE & tunnel

Measuring a Mountain for WS Base

by Alistair J. Clark
by Alistair J. Clark

Alistair Clark shares how he measures and assesses a new mountain for Wingsuit BASE…

(See An Incidental Culture for background on the importance of measuring)

Tombstone

Here is a beautiful jump that I opened this summer, I named it Tombstone for its obvious appearance. The general atmosphere of this area screams wild west, I can't help but picture gun fights, mining camps, gold panning, cattle rustlers and law men as I wander and explore this area. I first came across this mountain 4 years ago on an afternoon 4x4 adventure, it sticks out like a sore thumb and is impossible to miss when you arrive in this valley. I immediately fantasized flying down the big gully from the summit cliff, but I dismissed the idea assuming the cliff was too small and the terrain too flat. It's not that big a mountain anyways. 4 years later I would hike it with my girlfriend simply to stand on the top.

Measuring Process

It was July 27th, the sun was shining and we arrived at the hike around 9 am. I hadn't bothered checking this mountain for height or distance as I was already convinced it wasn't jumpable but I did bring my range finder just in case. We found the hike quite easily after having researched it on some hiking web sites, we made our way up the north side drainage. The summit is guarded by about 20m of 5.8 climbing, it's an easy free solo for any moderately experienced climber but definitely not a place you can afford to fall so I recommend being roped in. I found a route up it that I knew I could easily down climb so up I went. I measure with http://www.lasertech.com/TruPulse-360-Rangefinder.aspx. I was surprised to find out the cliff was big enough, 600 feet tall! After searching around a bit, I found a potential exit….. but there is a ledge.

A gross ledge 48 feet down, 16 feet out and the funnel shaped terrain trap below. — by Alistair J. Clark
A gross ledge 48 feet down, 16 feet out and the funnel shaped terrain trap below. — by Alistair J. Clark

The Ledge!

The ledge is 48 feet down and sticks out 16 feet at the smallest point in the middle of the picture. Visually it looks really easy to clear but my numbers say differently, I would clear the ledge by about 4 feet, that is not good enough for me, I also don't know what is immediately below the ledge so this is not an exit in my opinion. It is so important to measure, our eyes are simply not accurate, especially with the influence of wanting the jump so badly. After down climbing the summit block I had enough for the day and was ready to head home. Further measuring will have to wait for another day but I do have a renewed fire for this mountain. I will need to find a better exit, hike around and measure from the bottom of the cliff and I will also need to measure the flight line lower on the mountain as there is a huge potential terrain trap to clear if this mountain will be flyable.

Flysight Data

As soon as I got home I started researching the mountain on google earth, I need to know the overall height and distance and I need to compare those measurements to my http://www.flysight.ca/ files. This is not a complete tutorial, but this is generally how I assess my measurements.

I pick a flight file from my past that is not my best performance, one that I know I can repeat even on a bad day, this gives me a margin for error. I set my exit and zero the ground at the exit by using the time setting on the bottom of the graph, the exit is more definite and obvious on this setting. Then I set the bottom to horizontal distance not total distance, this is very important for accurate measurements. Total distance makes your performance seem a lot better than it is, do not use the total distance setting. Now I can make my list of measurements that I will keep in my cell phone as reference to the cliff measurements. I use 50' vertical increments and their corresponding horizontal measurements, that way I have lots of points to compare when I measure the cliff.

flysight flight profile — by Alistair J. Clark
flysight flight profile — by Alistair J. Clark

Baseline

Next I will export this file to my https://baseline.ws/ app and relocate it to the mountain I want to compare my flight to. There is a step where you will need the map co-ordinates to drop your flight file on, I get those co-ordinates from google maps. I only use this step to get a look at the general height and distance, I do not rely on this step for exact measuring or to predict terrain flying. Please follow the tutorials on both the Baseline and Flysight websites to make sure you are using accurate measurements.

Flysight file on google earth using the Baseline app. — by Alistair J. Clark
Flysight file on google earth using the Baseline app. — by Alistair J. Clark

My intended landing zone is the river bed, this one looks good. Now I need to go back to the mountain, find a better exit and measure the potential terrain trap. The following week I hike the mountain and find a much better, cleaner exit that I am happy with, I down climb from the summit and hike around the mountain to the front side to get a look at things.

Side view of the cliff as I approach the front side. — by Alistair J. Clark
Side view of the cliff as I approach the front side. — by Alistair J. Clark

From this side I can measure the cliff from the bottom, get an exact shape of the wall, measure the angle of the scree and all the necessary measurements to the potential terrain trap farther down the flight line.

The cliff from below — by Alistair J. Clark
The cliff from below — by Alistair J. Clark
The scree slope and potential terrain trap. — by Alistair J. Clark
The scree slope and potential terrain trap. — by Alistair J. Clark

The point of reference I choose is the bench of trees just to the right of the gully centre, that gives me a bit of an “out” in the gully if I don't clear the bench. Keep in mind I am also using flight measurements that already have a margin for error. My numbers work with this mountain, the total height being 2,800', the total distance is 1.2 km (I can safely fly 1.8 km from this hight), the cliff height is 600', the angle of the scree is 35 degrees (this puts me about 200' above the slope when my flight achieves that angle) and the terrain trap is 1,276' down and 1,327' out (my flight clears this by 90'). So now I have every number I need to accurately say I can jump this mountain. This is what it looked like from my perspective during the first jump from this exit.

My view moments after exit, it looks low but I trust my measurements. — by Alistair J. Clark
My view moments after exit, it looks low but I trust my measurements. — by Alistair J. Clark
Achieving glide right where I expected to be above the deck. — by Alistair J. Clark
Achieving glide right where I expected to be above the deck. — by Alistair J. Clark
Approaching the terrain trap with good height.
Approaching the terrain trap with good height.
Buzzing the corner on my way out of the terrain trap. — by Alistair J. Clark
Buzzing the corner on my way out of the terrain trap. — by Alistair J. Clark
Clear sailing from here to the landing zone, just the flare and deployment to consider next.
Clear sailing from here to the landing zone, just the flare and deployment to consider next.
Lots of height left over my landing zone!! That gives me room to play a little next time.
Lots of height left over my landing zone!! That gives me room to play a little next time.

Measurements are Vital

This is a great example of a mountain that should never be jumped without your personal flysight data and accurate measurements to compare to, the margin for error is just too small. I have taken 2 jumpers to this exit who are phenomenally better than myself, they have better exit performance and way more experience. The 2 jumpers I took asked me for all the measurements and brought their own rangefinder to double-check my claims; wisely they do not take anyone's measurements at face value and would never consider jumping it just because I did. I know this practice is why they are still going strong in this game.

I cannot stress it enough, measure the cliffs you plan to jump.

Avoid 'Follow the Leader'

These days it is far too common for jumpers to be practicing what I call “hand me down” or “follow the leader” base. In this dynamic one person will know the location of the exit, they will in turn share it with more people without taking all the necessary steps of comparing measurements. If they happen to survive the jump using this dynamic, it is a matter of time until inevitably someone without the capability gets taken to the exit and ends up dead on the scree or stuck trying to perform an emergency pull before smashing into that terrain trap. All it would take on this one is to glide out 90' lower after exit, that would definitely result in an emergency pull or worse. A cross breeze, a weak push, or any type of inefficient exit would be enough to put someone in a very bad situation here. I cannot stress it enough, measure the cliffs you plan to jump. If you choose not to measure for whatever reason, or at least get the accurate measurements from a trusted source, you are doing yourself and this beautiful activity a huge disservice. If you decide to go forward not measuring, you are putting the safety of yourself, other people, the reputation of this sport and access to hard earned exits at risk.

BASE Etiquette

On top of measuring I also practice a certain etiquette. The access to these jumps must be preserved, the safety for jumpers must be maximized, and we must pay respect to those who opened the jumps. My etiquette is as follows: if I didn't open it I need permission from whoever did to share the jump with others and I only share jumps in a manner that the opener agrees with. I know this isn't very convenient for people who want the jumps but need to be guided, or for those who like to guide others and use jump locations as a type of social currency. It does take more effort to achieve a jump responsibly but if you want to start jumping more technical exits, measuring and understanding is 100 percent necessary for your and this sport's survival.

Worrying Trend

this trend is exchanging safety and longevity for convenience and social status

The trend I am seeing is one that I so very badly want to curb. The trend is making jumps accessible to those who can't or won't make them accessible to themselves. This trend is exchanging safety of its participants and longevity of the sport for convenience and social status. I understand that in the beginning jumpers need guidance and can't be expected to self assess right away but that is what Brento, Heliboogie and other huge infinity walls are for. Finding a good mentor is also very important. Be very careful of the self-appointed cool guys pretending to be teachers and mentors, there are lots of them out there these days. Pick your mentors carefully, ask them lots of questions and pick your cliffs even more carefully.

Pick your mentors carefully, and pick your cliffs even more carefully.

Cheers everyone, safe jumping!

Want More?

Read Alistair’s personal account of 3 BASE deaths and why this caused him to adopt the doctrine of always measuring – An Incidental Culture

This article was originally published on @canadianwingsuiter

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