Some youtuber tried to sonar it to get the depth and also tried throwing some video camera in it but it's muddy and turbulent so it's hard to get the big picture of how it works.
What would really be cool would be to have the 3d geometry of the river, and run it through water simulation software ; put a rag-doll in and see how the current would pull you down.
Constructing the 3d geometry is probably an interesting engineering challenge. Although there exists some off the shelf underwater lidar solutions https://www.youtube.com/watch?v=YevvMcc6Zu4 and underwater drones, it's likely to be too turbulent (and with air bubble) for them to stay in place at a known position to work properly out of the box (but maybe not because it seems to be possible to scuba dive the strid https://www.youtube.com/watch?v=kUamSryCUK4).
With the way things are going, the easiest route will likely be to wait for summer in a few years time, and to do it whilst it’s dry. It has dropped to record low levels several times in the last few years, revealing much of the absolutely tortured pothole-ridden geology beneath, and the drainage which feeds it is failing to get replenished year on year.
Interesting story: my parents had a fashion business in Yorkshire, and one of their regular customers asked them to produce a t-shirt with the words "I jumped the strid" on it. We had no idea what the words meant. Turns out, in Yorkshire, jumping the strid was a way to express your love to your girlfriend. We got a few of those t-shirts made, and were surprised by the number of 50+ year old couples that bought them that summer!
(referencing Ken Liu's Dandelion Dynasty, which I just finished. Liu is the American translator for Liu Cixin's Three Body Problem, which has been discussed on HN, so other HN readers might be interested to learn that he also has his own fiction)
On the history page of York Sub-Aqua club, they refer to members having regularly gone diving in the "Stridd" at Bolton Abbey in years gone past [1]. The only other reference I can find to diving in the Strid is in Youtube comments [2], which apparently suggest that the dives stopped some decades ago.
It doesn't look particularly fast-moving, so I must be missing something here that accounts for the legendary 100% mortality rate. Unless there's a giant vortex of electric eels, this stretch of water looks tamer than what those extreme kayakers were up to in HBO's recent docuseries.
I heard it described as follows: the full force of the river you see upstream has been turned on its side and the current goes down. You can’t pull against that, especially against curved, mossy, wet rocks
So as if an elephant were pulling you down beneath the water and you only had your strength to grip against it. Can’t be done.
So parallels can be made to other places to show the danger. It's a slot canyon; only one that's generally constantly full versus empty most the year until the monsoon hits like those here in the US where I am. But the danger remains the same, the sandstone geology allows for it to create very deep and fast flowing situation due to Bernoulli's principle. Even more so for constrictions in the rock which form natural venturi.
<s>I looked but was not able to find CFM/CMM for the input and output</s>; but that would give a reasonable idea of what the volume of the canyon must be because what goes in must come out. So the volume of the flow at the outlet and inlet gives a very good idea of just how crazy it can be.
What I don't understand is how that works from a conservation of mass perspective. The water can't be literally flowing down at every point and keep a stable surface. I assume it's something more complicated, right.
In an incompressible flow (e.g. water under anything resembling normal circumstances), there is no net flow into or out of any given volume, i.e. a 3-D box or other shape. But the surface is 2-D! So you can look at a little box with its top at the surface and its bottom slightly below the surface. If there is downward flow out the bottom (and zero flow out the top, of course), there must be net inward flow in the sides. Nothing wrong with that.
This could happen if the river has constant speed and constant cross-sectional area everywhere but gets progressively narrower and deeper. The water moves inward because it has to get away from the encroaching banks and moves down to fill the deepening channel. If this is abrupt enough even in the absence of turbulence, the downward current a foot or so below the surface will be substantial.
Part of the difficulty of turbulent water is that it can really whip you and smash you around. It doesn’t necessarily look that violent from outside of the water, but you could be getting broken limbs and brain trauma in that kind of turbulence. The force of the water pressing you into walls and boulders is tremendous.
Loads of fatalities in turbulent water occur because the victim rapidly becomes unconscious in the water.
In addition to the explanations of the turbulent water smashing victims against the rock walls, presumably a very turbulent flow could also turn into a mixture of air and water, with a corresponding decrease in density such that it would be more difficult or even impossible for a person to maintain buoyancy.
It's an underground tunnel with a small exposed strip at the top.
the water can be circulating around the tunnel, flowing back and forth under the rocks. It can be pulling sideways or down at the exposed strip with the water circulating back up in the underground areas out at the sides.
I bet it's flowing horizontally but faster the deeper you go. You fall in, the higher speed flow at your feet apparently "sucks" you under due to its higher speed (higher inertia), like being grabbed by your ankles and yanked down.
Of course the flux of water into any volume is equal to the outward flux. But I would imagine the situation is that there are circulating turbulent branching streams of current pulling you down. If you were incredibly lucky, and not killed by impacting the walls, you might pop back up by catching a ride on another section of current.
What you are missing is that this is an extremely complex version of a drowning machine — very good read here [0].
Under the water is turbulence that just traps a person and keeps them tumbling underwater.
In addition the article points out that there are numerous rock outcroppings underwater against which an unfortunate person's head would likely get bashed, reducing or eliminating consciousness.
I also notice that the water is quite frothy and full of air bubbles. This reduces it's net density and thus reduces the buoyancy available to any objects that would otherwise float. It can be enough to sink ships [1].
So, basically, the turbulent water will pull you under, bash you hard against the rocks, give you less-than-normal buoyancy, and hold you under. It's kind of a toss-up whether you lose consciousness first from the head injuries or the lack of air, and after a few minutes of that, you're dead. Have a nice afterlife
I don’t know about in a kayak, but I imagine that the current is too strong for a swimmer to hold on. The water will also suck you down deep underneath, almost certainly lodging you into one of the tunnels for the short remainder of your life.
In a kayak if the waters too turbulent (frothy or foamy) you can lose buoyancy pretty hazardously and capsize really easily with poor chances of unaided recovery.
There's a few spots near me that are well known danger spots for kayakers due to this phenomenon.
The sides of the rocks are also angled out, so not only do you get sucked down, you get sucked down and out, so there's no chance of even swimming back up.
Ah, I was wondering about the extent to which it might pull you under. Like, is that quantified at all? Consistent or only in a few sections? And how does it compare with some of the world's other most dangerous rivers?
> The Strid (grade 5-) is a long thin section of river where the Wharfe narrows to 5-6 feet in places. The main problems are beneath surface in form of ledges which if you're swept under - you can forget it! At a higher level as seen in pictures, it's runnable. The pictures show med-high water and most of the ledges were covered. I'd have graded it at 5- this day. At lower levels it runs at class 5+ and many would portage, the ledges that trap you need divers to get to you and even good safety cover would be of little use in an entrapment situation. (2 tourists fell in at the Strid last year and one didn't emerge for nearly a week)
It's a pretty standard rating system. (I-VI--with the latter not being generally runnable) However, once you get to the highest levels there are unique features that can determine difficulty/danger. For example, if you do dump, is there a quiet section at the end of the rapid or is it miles of the same thing?
Don't know about quantified, but some of the underwater videos show bubble entrainment in some kind of shear flow 25+ meters down, which indicates a terrifying amount of velocity and power pushing downwards.
> What is known is that a powerful undercurrent will pull anybody that falls into certain death.
> The reason for the dangerous network of caves is just further up above the mouth of the Bolton Strid the river flows 30ft wide and a lot easier giving a more idyllic, romantic and tranquil flow before being disrupted by a geological formation that abruptly funnels hundreds of gallons of water through a tiny six-foot channel.
So, the surface appears tranquil, but under the surface is a swift turbulent undercurrent.
I've not seen the documentaries you refer. But kayakers know that danger of a water feature doesn't necessarily correlate with how violent it looks on the surface. Plenty of very quiet weirs are known to be fatal while plenty of noisy ones (though not all!) will spit you out unharmed.
It always warms my heart that The Strid is internet famous. My memory is walking by it and my grandad, not one for hyperbole, telling us how dangerous it was. Miss you gramps!
If you compare the above-surface parts of the video to the pictures from the article, you notice that the pictures were taken at "high water", where the gorge is filled up to the brim. In the video, there is at least one meter of near-vertical wall visible, so it doesn't look like an innocuous stream anymore.
Really, really creepy to watch. I kept gritting my teeth when he was climbing on the mossy rocks, wondering how easy it would be to join his camera. :(
I live 15 miles from there, its a beautiful, popular area, that is easily accessible via nearby carparks and riverside paths, so great for family visits. There are more challenging routes on the surrounding hills and moors, so attracts a variety of people there to enjoy the outdoors, its common for the large carparks to be completely full.
I can't comment on the mortality rate at the Strid, the photos and videos do not do justice of how dramatic it is and how loud the water is where it escapes from the narrows.
You only have to go a short distance downstream (1/4 mile) and there are safe paddling spots after the river widens again.
If you liked that, go to his Strid playlist and watch the one where he films underwater. Watching it, you can imagine how terrifying it would be to get sucked under water. Very creepy.
>He was said to have been swallowed by the Strid in 1152 after trying to leap across.
As an American it's always startling to casually see a date that far back in history, and know a specific event such as the death of a child was recorded, and has been remembered for nearly a thousand years.
Yep. I regularly drive 46 miles to visit my wife's family. The roads are long and straight, and the speed limits quite high.
We get passed on the highway when we're doing 120km/h. I don't imagine you can maintain those kinds of speeds on account of speed limits and winding roads. Possibly takes an hour or three?
When I visited relatives in the West Midlands of the UK, they treated any journey over 30 miles like an expedition into hostile territory, and so they were astonished that I'd drove 40 miles to hang out with my Mum for a few hours.
My wife attended graduate school 200km away and would leave and return the same day. At least one of the ways (depending on what time the class was) was in stop-and-go traffic for a decent part of it, taking up to 4 hours.
Ha, (USA - MS here), my mom lives 17 miles(27 km) away and I visit her regularly, and prior to my current job, I commuted 44 miles (70 km) daily for 3 years.
As a Brit now living in California I agree with your sentiment but a 10 hour drive for a week long trip was pretty routine in my childhood, usually once or twice a year.
Either visiting family in Cornwall (400 mile, 12 hour trip when we were young kids before the roads were improved, 8 hours when we were older) or camping holidays in France (usually two weeks.)
Counterintuitively, oral histories (and traditions) have been and may be a better long term store of information than written documents but someone in the future is going to find out for sure! There's the 10000 year Australian aboriginal tales about sea level rise that matched geological data and was on the front page a few years ago.
There's no video of anyone swimming the whole thing. The conditions vary wildly from one meter to the next.
> To save a click: the "100% mortality" thing is a local legend.
Middlebrow dismissal, given that there's no proof that it's not 100% and obviously there's no way to prove that it is. It's very easy to imagine a design that would kill 100% of swimmers, it would actually be surprising if there isn't somewhere in the world that would do it.
I don't think there's any way someone without a life jacket survives 3:40, or someone pulling them to safety at 3:54. The extremely bouyant kayak itself struggles at 3:54 to not go down. A ~neutrally bouyant human in that aerated water would be toast.
The place where they are swimming is the part where its 5 meters deep. Upstream it's 65+ meters deep, and when you watch the video there appears to be a zero chance anyone could survive that (watch the other videos down in the article)
There are tons of videos of people kayaking this creek [1], some with people exiting their kayaks and swimming in it and not dying. When did HN become a place where extraordinary claims without extraordinary evidence get defended by downvoting reasonable doubts?
Please don't make light of The Strid by describing it as a mere "creek". One video does not make "tons". Extraordinary claims require extraordinary evidence! This video is clearly fake, or if not perhaps the kayakers in this singular video are some kind of immortal demigods.
Eh, I know, internet literalism and all, but once something becomes deadly enough -- falling out of an airplane, going over Niagara falls, tangling with high voltage power lines -- I'm happy to call it "100% mortality" and chalk up the residue of survivors as "miraculous", instead of getting all "technically it's only 99.7% fatal...".
Sure you can, "causation without correlation" happens all the time in systems with feedback from unmodelled variables. A canonical example is correlating braking force with vehicle speed while driving downhill; if you're trying to maintain speed, your data's going to look like your speed remains relatively constant no matter how hard you brake.
(Or, I guess relevant here, you're not going to find much correlation between, say, getting guillotined and being dead 150 years in the future, even though getting guillotined absolutely does count as a cause of death in the conventional sense.)
Is that a definition of correlation inside the field of mathematics? Because the normal English definition of correlation just means a connection, and absolutely doesn't mean linear.
edit: Ah, Wikipedia intro suggests that yes it's specific within statistics (though still seems to not be a hard requirement to call something a correlation?): "In statistics, correlation or dependence is any statistical relationship, whether causal or not, between two random variables or bivariate data. Although in the broadest sense, "correlation" may indicate any type of association, in statistics it normally refers to the degree to which a pair of variables are linearly related." https://en.wikipedia.org/wiki/Correlation
The slightly more fun version of that example is that cos(x) and sin(x) have zero correlation. But if you plot a bunch of coordinates that are generated that way, you'll quickly notice a pattern...
You can easily view cos(x) as causing the value of sin(x) to change - if cos(x) starts going down, sin(x) will too soon afterward. If cos(x) starts going up, so will sin(x), soon afterward.
In fact, if you allow for a time lag between your data series, you will find that sin(x) and cos(x) are perfectly correlated.
I am in a sphere in space, and I throw a dart at a wall, and I measure the coordinates. I caused those coordinates to occur, yet there is no correlation between cause and coordinates. Or a coin toss.
Not if you count kayaking[1]. In general I doubt that this is more dangerous than other whitewater creeks. They are all death traps that people can't normally survive swimming in, especially if it's hard to get out. The article seems to be based more on local legend than actual facts.
My brother-in-law drowned in the Māwhera/Grey River on the West Coast of the South Island of Aotearoa New Zealand.
The geology of the river that got my BIL is very similar to the Strid - swift deep waters cutting through a limestone bed, creating shelves that currents and buoyancy can trap you under, eroding through to natural caves, or in the case of the Māwhera, eroding into the old coal mining tunnels that burrowed beneath the riverbed in the 1800s.
End result is a highly treacherous waterway. The Police Dive Squad refused to search for my BIL's body due to the shelves and tunnels, and the current.
So, yeah, this is more dangerous than your whitewater creeks, mainly because it doesn't look dangerous, but also because of the additional hydrological dangers that a sweet whitewater run doesn't have.
It's supposed to be especially dangerous because it doesn't look like a whitewater creek. There's a part where the river becomes narrow enough to jump across and the water appears calm but is extremely deep and fast moving. It's a popular beauty spot and the river can be mistaken for a shalllow stream.
The article is indeed of very low quality, though, and claims of it being "the most dangerous stretch of water in the world" are hyperbole at best.
Is that the Strid? They don't say the name of the location in the video or in the description. It also looks a bit different to me than the pictures and videos of the Strid.
I'm no whitewater expert, but this doesn't look like a near drowning to me. He probably attempts to roll but is obstructed by the rock and current, then exits just as assistance arrives. The hydraulic is potentially dangerous, but most of the circulation he's stuck in looks to be horizontal, and I don't see reason to think he couldn't have swum out if need be.
Not according to all the information discussed in the other comments.
> most of the circulation he's stuck in looks to be horizontal
This section has up to 60m depth, the underwater currents are extremely turbulent and will you pull you under the rock on the sides (the whitewater is just a 'slit' on the surface, there's a whole river running underneath). If he didn't have someone ready to pull him out in two seconds like in the video, it's a good bet he wouldn't make it out.
I don't believe much of what is said on the internet about the Strid. It's not a magical river. The Strid is dangerous, but it acquired that reputation by killing unprepared people who fall in. I've not seen much to indicate it's especially deadly to helmet and PFD equipped paddlers.
It's possible that the man depicted could have been dragged under an undercut if he'd swum the full rapids, but the video doesn't show evidence of that. Rather, he's pulled out of an eddy without much drama.
In a river, they're called strainers. If someone is caught against one, water pressure often makes it impossible to extricate themselves without assistance, and if their head is underwater when they become trapped, rescue may not come quickly enough.
They're also less predictable than a lot of other river hazards. It's possible to come around the bend and be faced with a big strainer that wasn't there the last time you ran the river.
And he was pulled out of the water by two other persons using a paddle. Before that he was stuck upside down under the kayak for a solid 10 seconds before another person grabbed the kayak. There was no indication that they could've uprighted the kayak under their own power (we can only speculate). The person didn't look like a happy camper afterwards.
10 seconds isn't long at all, and it doesn't look like he was stuck (probably just trying to roll before committing to the wet exit). He walks away under his own power in the uncut version. I've seen footage of far, far closer calls.
You'd hope to not fall out of the kayak, but stay in it (with the skirt keeping most water out of the body of it), and do an Eskimo roll. The kayak, being very buoyant with all that air inside, would be unlikely to be sucked under. If you can't do an Eskimo roll, you would drown (presuming the whitewater traps you in the one spot rather than pushing you downstream)
I talked to someone in a reticulated pedal boat the other day about how he rescued a kayak instructor from drowning because he could not reverse himself from being turned upside down in front of his own class who didn't realize he was serious about tapping the hull to indicate he needed help. He calls kayaks "death traps". I believe him.
Wet exits are the fallback and aren't hard. Just pull the strap on the spray skirt or, failing that, grab a double-fistful of skirt and pop it off the side.
Sometimes people tuck the grab-loop inside their spray skirt by mistake, which is why it's worth practicing one of the back-up techniques. It's also possible for an improperly burped dry-suit to trap someone in a boat (I know of at least one fatality in this way). I wouldn't expect an instructor to make these mistakes, but it's possible.
Translation for pedants: Lots of people die - especially know-it-all idiots, thrill-seekers, and show-offs. We locals - whose taxes pay for the paperwork & such after each death, by the way - are utterly sick of it. Go earn your bloody Darwin Award somewhere else, arsehole.
This reminds me of 'mekedatu' ('The Goat Cross') gorge in the path of river Kaveri in India https://en.wikipedia.org/wiki/Mekedatu. The water here is similarly deceptive making it extremely dangerous. Many lives have been lost.
OT: Am I wrong in thinking the correct word to use here would be "deceptive" instead of "deceiving"? "Deceiving" in this context just sounds wrong to me but I feel like I'm suddenly hearing it a lot these days.
They are words that have come to English via different routes. "Deceiving" is the present participle of "to deceive", with the earliest common ancestor being the Latin noun decipio. The passive past participle of this noun in Latin is "deceptum", and on this form it is common to derive an adjective with a postfix "-ivus", hence "deceptivus". This word then enters English in a parallel manner, giving "deceptive".
In this case they have identical meaning in context, but there's frequently unpredictable semantic drift in these pairs, if both do end up in English.
I remember seeing a few videos on this, it's super interesting because there are accounts of how dangerous it is, going back hundreds of years. Fascinating stuff.
> The most infamous life claimed by the stride is William de Romilly, the son of Lady Alice de Romilly, who owned the land. He was said to have been swallowed by the Strid in 1152 after trying to leap across.
Why was he infamous? I'm not finding much information on him at all.
The Strid's calm apperance is what scares me (calm at least from the photos, I imagine it's loud in person). Would admire from afar, avoid any off chance of slipping in.
Yeah. That Youtube video of the guy testing the depth with a fishing rod... builds my anxiety just watching him get that close. If that were a 2,000ft cliff instead of water, I wouldn't get half that close! Knowing how deadly the water is... one slip... anxiety building.....
It would be pretty cool to send an underwater drone down there, with power/video line to the surface, so it would be pretty lightweight and enough illumination to see in the water.
I’ve been thinking about a Gladius “Chasing Dory” for a while as they are comparatively reasonably priced. But even at a few hundred bucks I don’t think I’d want to risk it in there!
I kinda doubt you'd get any useful control with those currents. Might as well just drop a camera in there on a rope or a stick (which has already been done).
As soon as I saw the headline I thought that it sounds like something Tom Scott would create a video about... and then there is his video right in the article.
The one tiny issue with that plan is that if they are an experienced scuba diver and were given that request then they’d they’d nope the hell out of the vicinity faster than a human can blink. By definition any scuba diver attempting that is either the most inexperienced one in existence or suicidal.
A similarly mad plan would be draining it. Create a bypass and then pump out the water from the deep pockets and see what's in there.
I imagine there's some political challenges to that, but from an engineering perspective it's old hat. High likelihood of being sued and shut down by the local government, but low likelihood of anyone dying.
I thought the water itself was so impure that if you drink it then the mortality rate is 100%. That’s what the title suggested to me. But turns out it’s the river thats dangerous.
HN submission titles can be improved based on feedback, which is one of the functions of comments. As you can see, the usage no longer appears in the title.
The meaning being understandable isn't an effective criterion for good writing, because even egregiously poor writing with multiple errors of grammar, spelling and word usage can often be understood.
The appearance of this article on HN strikes an uncanny valley for me. I independently recalled and told a friend about this river just a few hours ago, having not thought of it or done any digital interactions with the idea in probably more than a year. I searched it on DDG to show a picture. Now, suddenly, it’s #3 on HN.
Am I going mad? Is the surveillance state so deep in my subconscious that I fail to notice it’s observations? This article isn’t even tech related, why is it here?
There’s a popular video heavily recommended on YouTube right now which has likely bounced around link aggregators like Reddit, HN, and other blogs etc. Odds are you saw some derivative of that.
This is just the regurgitation of the internet causing a deja vu effect
Either we’re all living in your dream (not terribly likely from my perspective) or you’ve stumbled upon one of life’s great joys: the so-called “delusion of reference”, a fun trick our minds like to play on us sometimes. Congrats on your unsettling coincidence :)
Just the Baader–Meinhof phenomenon at work! Or perhaps a synchronicity, if you are inclined to believe in such things.
A similar thing happened to me the last time the Strid popped up on Reddit and HN. It was only a day after I had just returned from a popular walking route which passes alongside it and the Abbey.
This happens to me frequently too. Think of something obscure then it appears on HN. It is neither coincidence or surveillance. Reality is an information fractal.
What would really be cool would be to have the 3d geometry of the river, and run it through water simulation software ; put a rag-doll in and see how the current would pull you down.
Constructing the 3d geometry is probably an interesting engineering challenge. Although there exists some off the shelf underwater lidar solutions https://www.youtube.com/watch?v=YevvMcc6Zu4 and underwater drones, it's likely to be too turbulent (and with air bubble) for them to stay in place at a known position to work properly out of the box (but maybe not because it seems to be possible to scuba dive the strid https://www.youtube.com/watch?v=kUamSryCUK4).