Believe me when I say there is no missing the Frank Slide as you drive along Highway #3 through the Crowsnest Pass in southern Alberta, near the British Columbia border.
I’m a sucker for geologically related stories. Past articles I’ve posted include the formation of the Baja Peninsula, the fossils of the Burgess Shale, time travelling through the Canadian Badlands, the journey of Big Rock erratic, and the origin of Victoria Falls. So now – the fast, furious and unforgiving Frank Slide.
From either direction you see the evidence of a massive rockslide well before reaching the area. A large bare section of the mountain is easily visible as you drive westward. Then soon the landscape changes from green hills and trees to rocks and boulders – including some very enormous ones!
The unimaginable happens
On April 29, 1903 at 4:10 AM, the quiet coal mining town of Frank, Alberta, Canada, population 600, is abruptly awoken by sound and rumbling later reported heard 200 kilometres (125 miles) away.
A section of Turtle Mountain some 1000 metres (3300 feet) wide, 425 metres (1390 feet) high and 150 metres (490 feet) thick, breaks free and careens towards the town of Frank.
In less than 100 seconds, the rock debris rockets down the mountain, across the valley floor, and partially up the hills on the opposite side, annihilating the Frank Mine buildings, the railway camp and the east side of Frank on its way. The video below illustrates this.
The rockslide reaches speeds up to 110 kilometres/hour (70 miles per hour). In total the Frank Slide debris covers 300 hectares (750 acres) with an average thickness of 14 metres (47 feet).
Try to imagine it. The sound, the wind, the ground shaking. All in one and a half minutes. Fast, furious and unforgiving!
No one has a chance to react as most are still in bed. It is dark out so the people of Frank cannot see what is coming. About 100 to 120 individuals are in the path of the rockslide. Of these, an estimated 70 to 90 people lose their lives. We will never know the exact number of casualties as only 12 bodies are recovered shortly after the catastrophic event.
20 miners are working at the Frank coal mine at the time of the rockslide. Three unlucky souls are taking a well deserved break on surface and don’t stand a chance. The remaining 17 miners are trapped in the mine, but alive. After unsuccessfully trying to dig their way back out through the entrance, one of the miners has an idea. They dig through a coal seam that reaches the surface.
After several grueling hours they breath in fresh air, but emerging is too dangerous due to rock fall. They divert there digging to a safer spot on surface. All 17 survive.
The rockslide obliterates the railroad camp, killing all 12 rail workers residing there. Miraculously, 128 other rail workers avoid the same fate. Their scheduled train ride from a small town 90 kilometres (55 miles) for the previous day did not materialize.
One brave Canadian Pacific Railway brakeman rushes across the very unstable field of rocks, to warn an oncoming train about the rockslide. He is successful, and most likely prevents even more casualties.
What caused the Frank Slide?
In a foreshadowing way, stories passed down by the Blackfoot and Ktunaxa First Nations refer to Turtle Mountain as “the mountain that moves.”
The Geologic Survey of Canada (GSC) concludes the primary cause of the slide was a precarious anticline formation. In simple terms, older limestone rested on top of younger, softer rock resulting in an unstable, steep cliff.
Cracks in Turtle Mountain allowed water to penetrate the critical stress areas within. A warm and wet winter created repeated thawing and freezing within the cracks of the mountain. On the night of the Frank Slide, a sudden dip in temperature to -18 C (-0.4 F) may have contributed to the breaking point.
A more controversial possible contributing factor, is the active coal mining under Turtle Mountain at the time of the Frank Slide. Later studies theorize the mountain was in a state of unforgiving equilibrium. This means the coal mining activity may have been enough to upset the equilibrium and allow the other destabilizing factors to take hold.
Why was the Frank Slide so Fast, Furious and Unforgiving?
Two theories have been debated as to how the rockslide was able to move so rapidly and reach so far.
The “air cushion” theory suggests that a layer of air became trapped between the rockslide debris and the mountain. This allowed the rock to travel faster and farther over a cushion of air.
The “acoustic fluidization” concept theorizes the large mass of moving material generated seismic energy that reduced friction between the debris and the mountain, again allowing faster and farther travel.
Either way, the Frank Slide acted very much like a typical large snow avalanche, so the new term of “debris avalanche’ was created.
Whatever the cause, I think one could use “fast, furious and unforgiving” to describe the Frank Slide.
Wow this is terrible! Those innocent people. Nobody could have known I suppose. I love geology too.
Terrible indeed! It happened so fast in the middle of the night. It would have happened totally by surprise. Who ever thinks those monster mountains that look so permanent could be that fragile?
What an awful tragedy! I wonder if it could happen again in the same or a nearby place. Thanks for sharing this interesting story.
Hien, apparently there is serious concern that another slide could occur in the area. They now have extensive monitoring equipment on the mountain to forewarn of any ‘movement’. They also relocated the town just a few years after the slide, so very few people now live immediately below the mountain. There still is a railway and highway mind you.
How intense Dave. Nature is so powerful. We cannot stop some of these forces; we can just hope not to be in the wrong place at the wrong time.
Yes the visual impact of this area is powerful indeed. Makes one feel rather insignificant in relation to nature. Life can be so unpredictable in the spectrum of ‘right place at right time’ or ‘wrong place at wrong time’.
I have been by this site a few times and always feel an eerie sadness knowing part of a town is under those rocks. I found the interpretive centre to be very informative. Imagine the shock of the surviving townspeople to be awakened by this. An excellent post, Dave.
Thanks so much Darlene!
Yes, I had that same feeling, knowing most who perished in this rockslide were never found, and the shock felt by those who survived.
We’ll definitely need to go back to spend time at the interpretive centre, as when we got there it was swarming with school children so it wouldn’t be a peaceful stroll through the displays. 🙂
Wow. Great post. It is such a tragedy but I loved learning about the miners (what an ordeal) and railway worker whose lives were spared. As always, your video and photos bring it all to life. Thanks.
Yes the survival stories were incredible. I tried imagining being trapped in the mine and endlessly digging through a coal seam to survive. Yikes, made my hands sweat and heart pound a little faster!
what an awful tragedy! nature is gentle and beautiful but can cause rage and fury when pushed to the limits. so sad.
So true. The town was only 2 years old when the tragedy struck! I thought about those people who settled there hoping for a start of a new and vibrant town, with everything changing in 100 seconds! As you said, nature can be both beautiful and ruthless!
Thanks for writing Dave. I find all of your articles to be very interesting!! Carry on!
Thanks Phil! So glad you’re enjoying the articles.
I shall carry on!
Those poor souls that perished under these awuful rock slide…how terrifying it must have been for them. Although perhaps it has happened so fast they didn’t even have time to be scared. I am glad there were at least many survivors, something to be grateful about. Thanks for sharing this tragic story Dave.
Your welcome Gilda!
When I tried to imagine the actual event, I think you are right that those who perished probably had no time to think or react to the chaos around them. Over the years following the Frank Slide, apparently rumours spread that the entire town was wiped out, so many people today still think the entire town was hit by this wall of rock debris. So glad that wasn’t the case!
How sad for the unlucky people caught in this event, but amazing more weren’t killed. Those workers who didn’t get their train ride must have thanked their lucky stars.
The lottery of life! I imagine those rail workers who missed their transport were shocked to hear what happened. Maybe some survivors guilt as well?
Oh my goodness, that’s a horrendous story Dave. All those people. how tragic. Nature can be very unforgiving at times.
I like the geologial details you provide. Fascinating.
Thanks Shannyn. Yes, nature doesn’t have too much of a conscious!
I was pretty light on the geo-description, but I didn’t want people to fall asleep 🙂
Great story, Dave, and told in a way that even a non-geology kind of person can understand.
As others have said, we think of mountains are solid, permanent structures. A story like this one is rather sobering. 100 seconds doesn’t give any hope.
Thanks Joanne. This event sure shows how even the big old Canadian Rockies are ever changing. Extremely bad fortune that the town of Frank was caught in one of those rare extreme geological alterations!
Wow! I can’t even imagine. This must have been terrifying – like a train crash only about 100 times worse. Fascinating post.
So very hard to imagine what went through the Frank residents minds and hearts as the sound of 1000 trains came so fast and furious in the dark of night.
Mother nature has a way of reminding us who is boss. Hopefully, those who perished never knew what happened.
So true Laura! And I imagine the disaster was so rapid, people didn’t have time to figure out what was happening given they were most likely awoken from deep sleeps.
Fascinating but sobering. Rock slides and snow avalanches have always freaked me out a bit. They have the same terrifying nature as a huge wave of water – the power of momentum and the ability to just plow down anything in their paths. Nature is so awesome and yet so frightening sometimes!
So true. I was once caught in a rogue wave, and luckily escaped any harm (other than losing my sunglasses). The power of it was immense, yet I can’t comprehend the magnification of this rockslide in comparison. Yes, we must be respectful and aware of the potential dangers in the mountains (and ocean).
I always enjoy your geologic graphics and explanations, Dave, and this Frank Slide post was truly fascinating, albeit tragic. I heard myself groaning sympathetically as I read of the disaster and demise. Pretty amazing that anyone survived, and the 17 miners climbing out is an awesome tale. The heroic train brakeman story is heartwarming. Interesting about the old limestone on top of newer, the air cushion theory, and other speculations. Great job of showing perspective with the size of the boulders with the car, and the mass of rocks with your tiny red-jacketed body. Excellent post, thank you.
Thanks so much Jet. I really appreciate your feedback. It’s good to find good news stories within the overall tragedy. I too was fascinated by the ability of the minors to dig their way out. Also, it was quite precarious walking on the boulder field, so I too am impressed that the train brakeman was able to clamber over what would have been, a very unstable debris field.
I like the burst feature on my phone so I could capture the passing vehicle in front of the massive boulder (and delete the other 20 burst photos :))
How awful….I’ve never seen or heard of anything like this….great post, Dave…appreciate it….very informative. Mother Nature is in charge…this just reiterates it!!
The power of Mother Nature. Incredible and horrific….the number of lives lost. In all of my years living in the Colorado Rockies, I have seen small landslides, but nothing even close to this magnitude….bizarre. Thanks for sharing Dave, very informative!
Yes, standing at the base of the mountain in the rock debris makes you realize the shear power nature holds and occasionally wields! This size of rockslide is so very rare, yet seeing so many areas in the mountains strewn with large boulders with shear cliffs above makes you realize is does regularly happen (in geologic time that is).
And no problem with the double comments. Have been there, done that 🙂
Sorry for the two posts….operator error on my part..:)
Wow, fast ands furious says it all Sue and Dave – what an interesting story!
Yes, it was an easy title to pick once viewing the area and learning about what happened.
We visited the Frank Slide site on a family trip when I was a kid, and I was staggered even then by the extent of the devastation. The speed and sheer volume of those rocks is amazing (in a horrifying sort of way). That site certainly cured me of any desire to live at the base of a mountain.
How’s this for a tardy response 🙂 – stumbled across it this morning. oops.
Yes, visiting the frank Slide is a sobering experience!
I also wonder of those who choose to live under dormant or even active volcanoes. What are they thinking?
Fascinating read. While tragic that people lost their lives, one cannot help but be astounded by the power and drama of nature. Mining be it for coal or diamonds.. is probably one of the most dangerous jobs out there, every single day. The theories of why it was so fast furious and unforgiving are very interesting and I can see why this topic fascinates.
Thanks Peta (a rather delayed response I know – sorry about that).
When one thinks of coal mine accidents, it usually revolves around explosions or collapses – not a mountain falling down on top! To think the mine itself was the savior on that day!
Nous y sommes arrêtés en juillet 2022. En revenant de Vancouver, nous avons découvert ce site et cette désolante et triste histoire. Le musée nous présente la situation avant et après la tragédie et le *documentaire* acté nous résume bien ce qui a du se passer. C’est très intéressant ( pour l’histoire ) mais combien épouvantable pour ces victimes et aussi les survivants voyants leur vie ainsi bouleversées.
Voyageurs dans l’ouest, faites le détour. C’est près de Calgary ( au sud ) et la région est très belle.