Flatirons Scrambling Risk Assessment Article

https://boulderreportinglab.org/2025/04/10/boulders-flatiron-scrambling-fatalities-how-dangerous-is-it-really/

I saw this first on the Climbing website but it's also here. While not wanting to dive into the methodology or even the conclusions, I think there's always merit in trying to do some objective self-analysis of risk. Thoughts?

Peter Beal wrote:

https://boulderreportinglab.org/2025/04/10/boulders-flatiron-scrambling-fatalities-how-dangerous-is-it-really/

I saw this first on the Climbing website but it's also here. While not wanting to dive into the methodology or even the conclusions, I think there's always merit in trying to do some objective self-analysis of risk. Thoughts?

More weed for sure 

The numbers seem about right to me. I actually thought it would be a bit safer, not so close to base jumping and closer to driving. I’m very aware of the risk stacking up over time given how often I head up there.

As I get older I find it increasingly difficult to make a risk decision on low-probability/high-consequence events. I think it is ridiculous to say that the rewards of climbing Freeway (a fun hour) are worth the potential cost (death). But of course I will continue to do it since I believe I will beat the odds.

I swear I heard Jon Krakauer say that the rewards in climbing are totally worth the risk until something bad happens and it is totally not worth it. I thought it was in a documentary about climbing in Antarctica, but I asked him about it one time and he denies ever saying it! But I thought it really captured the conundrum.

I have to say that at my age I feel like it’s easier to justify the risks since I have survived 50 years of climbing and the loss of my life is now is lower consequence and I am much closer to my inevitable end anyway.

A lot to lose, very little to gain. 

My first thought is that it's really hard to estimate number of Flatiron scrambles. Strava might be the best data source out there, but extrapolating from Strava to reality is unfortunately really difficult. I've been up Freeway dozens of times, none of which is on Strava. I don't think that any of my Flatiron scrambler friends record their data publicly on Strava. I'd guess that the Satan's Minions (scrambling club) do, and people going for FKT, etc., but probably not a lot of more casual climbers and all the CU kids and their friends who scramble on a lark or as a rite of passage.

Whatever the author's assumption was about recorded vs. non-recorded scrambles, it has to be a WAG (Wild-Ass Guess). No fault of the author's, just the nature of the data. If someone really wanted to get a handle on the application of Strava data, you'd probably need to develop and implement a methodology to sample people approaching the base of popular scrambles and ask them if they will be recording on Strava. Which I can't imagine anyone doing.

To the OP's question about objective self-analysis of risk, this is raw for me right now having very recently lost a friend. That friend was an experienced free soloist who scrambled the Flatirons and in Eldo regularly and had a ton of alpine experience. He also BASE jumped, sky-dived, skied, etc. He didn't die from any of that. He fell while casually picking up a piece of trash from a ledge in his approach shoes. The nature of risk is that something can be very low probability and extremely high consequence. We can't guard against all risk.

Me, I will continue to strive to be conscious of risk and to push my limits gently under conditions of reasonable safety. Like the saying goes, push your grade or push your gear (safety systems), but not both at the same time. I'm not interested in flirting with danger for thrills, but I'm also not interested in sitting on my couch all the time. Everyone finds their own balance.

I feel okay scrambling low fifth class given my onsight lead ability and experience with low-angle slab, but I definitely don't recommend Flatiron scrambling as a casual activity for new climbers or non-climbers. Anyone thinking of scrambling in the Flatirons should first go with someone who knows the route. Getting off-route can go south quickly. I'd also take wet or icy conditions very seriously. A small change in friction can radically change outcomes.

David House wrote:

The numbers seem about right to me. I actually thought it would be a bit safer, not so close to base jumping and closer to driving. I’m very aware of the risk stacking up over time given how often I head up there.

As I get older I find it increasingly difficult to make a risk decision on low-probability/high-consequence events. I think it is ridiculous to say that the rewards of climbing Freeway (a fun hour) are worth the potential cost (death). But of course I will continue to do it since I believe I will beat the odds.

I swear I heard Jon Krakauer say that the rewards in climbing are totally worth the risk until something bad happens and it is totally not worth it. I thought it was in a documentary about climbing in Antarctica, but I asked him about it one time and he denies ever saying it! But I thought it really captured the conundrum.

I have to say that at my age I feel like it’s easier to justify the risks since I have survived 50 years of climbing and the loss of my life is now is lower consequence and I am much closer to my inevitable end anyway.

The numbers get a lot more tame when you exclude deaths before the 1950s (less general  knowledge about the route(s), less traffic, less access to accurate weather reporting and deaths from climbers with "unknown" or no scrambling experience). Obviously, the deaths from experienced climbers happen, and are of course concerning, but it still is relatively pedestrian risk overall. 

I think the numerical risk assessment isn’t really worth reading.  It is an interesting thought experiment, but the underlying data and assumptions used are not good enough to really provide any kind of valuable probabilisitic insight.  

I would be interested in seeing what kind of info Rocky Mountain Rescue Group has on scrambling incidents.  I feel like an Accidents in North American Climbing style write up focused on specific Flatirons scrambling accidents would probably be very interesting and worth reading.

L Kap wrote:

My first thought is that it's really hard to estimate number of Flatiron scrambles. Strava might be the best data source out there, but extrapolating from Strava to reality is unfortunately really difficult. I've been up Freeway dozens of times, none of which is on Strava. I don't think that any of my Flatiron scrambler friends record their data publicly on Strava. I'd guess that the Satan's Minions (scrambling club) do, and people going for FKT, etc., but probably not a lot of more casual climbers and all the CU kids and their friends who scramble on a lark or as a rite of passage.

Whatever the author's assumption was about recorded vs. non-recorded scrambles, it has to be a WAG (Wild-Ass Guess). No fault of the author's, just the nature of the data. If someone really wanted to get a handle on the application of Strava data, you'd probably need to develop and implement a methodology to sample people approaching the base of popular scrambles and ask them if they will be recording on Strava. Which I can't imagine anyone doing.

I disagree-- this is one of the more rigorous attempts i've seen to quantify the risk of free-soloing. It's not perfect, but should be order of magnitude correct.

With respect to whether using Strava to come up with the denominator- I assume that the authors assement of 21-51K scrambles/year has some sort of correction factor built in for unrecorded climbs. Just based on the numbers, it must: 51K scrambles/year is 135 scrambles per day....

In any event, i think it's reasonable to think that freesoloing the flatirons is about 10-100X less dangerous than a BASE jump.

MP wrote:

I disagree-- this is one of the more rigorous attempts i've seen to quantify the risk of free-soloing. It's not perfect, but should be order of magnitude correct.

Order of magnitude change in accuracy is a big deal for likelihood of dying. 

With respect to whether using Strava to come up with the denominator- I assume that the authors assement of 21-51K scrambles/year has some sort of correction factor built in for unrecorded climbs. Just based on the numbers, it must: 51K scrambles/year is 135 scrambles per day....

This is the WAG. 

In any event, i think it's reasonable to think that freesoloing the flatirons is about 10-100X less dangerous than a BASE jump.

You think it's reasonable based on what? Serious question. 

L Kap wrote:

You think it's reasonable based on what? Serious question. 

His numerator (# of deaths) is accurate; his timeframe (years) is accurate; and I walked you through how his denominator (total # of free solos per year on the flatirons) was probably correct within an order of magnitude. So it's the best (not perfect, but still the best) attempt at quantifying the risk of free soloing that i've seen. If you have a better, more accurate way to come up with a number, i'm all ears. 

This is a flatirons-specific calculation. I'd note that applicability of the number beyond the flatirons would be limited if , say, the climbs there are particularly chossy, or if there are some other location-specific issues to account for (colorado people are high all the time; locals use it to commit suicide; etc...) 

L Kap wrote:

Order of magnitude change in accuracy is a big deal for likelihood of dying. 

When the author uses the estimate to show that the risk of scrambling is between driving and BASE jumping (a difference of 4 orders of magnitude), it is completely acceptable to use an estimate with a single order of magnitude error.

One (minor) issue i take with the language of Simon's article is stating that the frequency statistics are "risk". I'd prefer he used the term "rate". 

Frequentist mindset vs Bayesian mindset, to be reductive.

-

"Although each individual scramble carries the same individual risk..."

I think I generally understand his point and don't disagree, but, as it's worded, I *literally* disagree with that statement .

The scrambles when it's icy or wet have more risk.

The scrambles when tired or emotional and distracted have more risk.

The rates representing general frequentist risk may not change much with every additional scramble, but the personal individual risk varies, due to a multitude of bayesian considerations, every time.

---

Otherwise, I appreciate the data compilation and numerical analysis, the quantitative thinking about relative risk, and the acknowledgement that "scrambling" is a dangerous activity worth thinking twice about when considering the risks and rewards.

-----

Also: FWIW, and not to thread-drift, my personal semantics is "scrambling" when a ropeless fall has a 50% or better chance of survival, "soloing" when a ropeless fall likely means death or life altering injury.

I tend to think that I "scramble" the 2nd Flatiron (with moments of solo-esque controlled risk) and I have "soloed" the 1st & 3rd Flatiron (with moments of "scrambling" interspersed amidst the "solo" terrain).

-

i.e. 

Fall while "scrambling"? 

Ouchie! No bueno, homie. Hope you have good health insurance.

Fall while "soloing"?

My condolences to your loved ones.

-

Currently I love scrambling the 2nd, and when I'm feeling adventurous, I love scrambling or soloing a few other relatively easy or manageable-risk formations; but soloing the 1st or 3rd is currently outside my comfort range and risk/reward framework of desirability.

(Thanks for sharing, Peter!)

FWIW, the times I have scrambled the 2nd Flatiron I did not record on Strava and can't imagine many serious climbers would; nevertheless I'm sure the numbers are good enough. 

My instinctual reaction is to reject the authors claim, "...you should also consider the cumulative probability risk (essentially the potential excess mortality rate). In other words, the more often you scramble the Flatirons, the greater your risk of death over time."

Of course, each time you expose yourself to that risk there is... risk, but I would contend that each person carries a very different probability of falling and that probability goes down with each subsequent pass of a route, at least until you become complacent. In other words, a CU kid in tennis shoes carries a much higher probability of coming off than does a 5.12 slab aficionado in approach shoes; this might not be the case if the biggest risks were rockfall or some sort of objective hazard but assuming you keep the forecast in mind, your risk of coming off Freeway is mostly a function of skill and route knowledge, in my estimation. 

I do acknowledge that I like scrambling the Flatirons and may just be rationalizing it for myself. 

Devan Bee wrote:

When the author uses the estimate to show that the risk of scrambling is between driving and BASE jumping (a difference of 4 orders of magnitude), it is completely acceptable to use an estimate with a single order of magnitude error.

I guess it depends on what conclusions are meaningful. "Risk of Flatirons scrambling is somewhere between BASE jumping and driving" is not especially meaningful to me, but it may be to others.

I do appreciate the author's attempt to quantify risk using available data. I outlined in my previous post how the analysis could be sharpened by sampling scramblers in the field for Strava use, but I doubt that's a study that anyone would be motivated to do. 

Article was interesting but ultimately I think if we were asked with no data to rank to risk of those three activities we'd have come up with a similar rank.. I mean cars have airbags.. and basejumping is yeeting yourself off something with one shot to stop it  Scrambling falls in between . It's not hard to make this conclusions lol 

Michael Spiesbach wrote:

Article was interesting but ultimately I think if we were asked with no data to rank to risk of those three activities we'd have come up with a similar rank.. I mean cars have airbags.. and basejumping is yeeting yourself off something with one shot to stop it  Scrambling falls in between . It's not hard to make this conclusions lol

"Scrambling falls in between"

I see what you did there

Andrew Giniat wrote:

My instinctual reaction is to reject the authors claim, "...you should also consider the cumulative probability risk (essentially the potential excess mortality rate). In other words, the more often you scramble the Flatirons, the greater your risk of death over time."

Author's statement merely shows that the author has knowledge of statistics.

For example, flipping a coin has 50/50 split between heads/tails. It does not matter how many times the flip occurs the odds of NEXT flip are not affected. But, the problem can be reframed - given a number of flips, what are the odds of at least 1 result being, say, heads up. Probability of getting the single desired outcome will get higher the more times you flip the coin

Here is a simple online calculator, choose "at least" in the "I want to have" field - https://www.omnicalculator.com/statistics/coin-flip-probability

Now, imagine odds of you encountering a random event with fatal consequences is 1%.
You would go to that widget, specify 0.01 for probability, 1 for heads.

After 1 event, probability of adverse outcome would be 1%, no surprise
After 10 events - 9.5%
After 100 events - 63.4%
After 1000 events - 100%

And, so forth.

amarius wrote:

Author's statement merely shows that the author has knowledge of statistics.

For example, flipping a coin has 50/50 split between heads/tails. It does not matter how many times the flip occurs the odds of NEXT flip are not affected. But, the problem can be reframed - given a number of flips, what are the odds of at least 1 result being, say, heads up. Probability of getting the single desired outcome will get higher the more times you flip the coin

Here is a simple online calculator, choose "at least" in the "I want to have" field - https://www.omnicalculator.com/statistics/coin-flip-probability

Now, imagine odds of you encountering a random event with fatal consequences is 1%.
You would go to that widget, specify 0.01 for probability, 1 for heads.

After 1 event, probability of adverse outcome would be 1%, no surprise
After 10 events - 9.5%
After 100 events - 63.4%
After 1000 events - 100%

And, so forth.

  

For sure, you pull the one arm bandit an infinite number of times and eventually you're going to get a jackpot. My larger point was really that playing the slots and flipping a coin are pure chance, whereas one's odds in scrambling are highly dependent on experience and skill, at least to a point. 

amarius wrote:

Now, imagine odds of you encountering a random event with fatal consequences is 1%.
You would go to that widget, specify 0.01 for probability, 1 for heads.

After 1 event, probability of adverse outcome would be 1%, no surprise
After 10 events - 9.5%
After 100 events - 63.4%
After 1000 events - 100%

By my math, you’d only have a 99.996% chance of death after 1,000 events in this scenario. Not that bad!

For real though anyone who find this general concept interesting should google micromorts. A micromort is a one in a million chance of death. The lethal risks of various activities can be estimated in micromorts and compared against each other. The hypothetical event here would have 10,000 micromorts (a lot). The average person has about 20 micromorts per day from all causes (overall risk of death), varying highly with age, and only about 1 micromort per day from non-natural causes. Basejumping is 430 micromorts per jump, and an ascent of Everest is 37,000 micromorts!

Of course these are average values and don’t take into account the possibility of subpopulations with varying risk levels. That’s a good thing, because it lets us do the necessary mental gymnastics to justify our risky choices while convincing ourselves the statistics don’t apply to us.

https://en.m.wikipedia.org/wiki/Micromort

Collin H wrote:

By my math, you’d only have a 99.996% chance of death after 1,000 events in this scenario. Not that bad!

If my math is mathing, that turns out to be 43 anti-micromorts! Super good enough!