23 Bulldozers Raced a Rising Lake Near Yellowstone (1959)

Added: 2026-05-10

[00:00:00]August 27th, 1959.

[00:00:03]Madison Canyon, Montana. [music] 23 bulldozers are cutting into a wall of fractured rock that did not [music] exist 10 days ago.

[00:00:12]Behind them, a lake is forming where a campground used to be.

[00:00:17]The water is rising at 30 acre-feet per hour.

[00:00:20]In front of them, the ground shakes every few minutes with aftershocks strong enough to crack pavement.

[00:00:27]If they stop, the lake overtops the debris, carves through it, >> [music] >> and sends a flood wave straight at a town called Ennis.

[00:00:35]600 people live in Ennis. Nobody has told them to leave yet.

[00:00:39]>> [music] >> This is the story of the largest equipment mobilization in peacetime Montana history. Built on a mountain that killed [music] 28 people 10 days earlier.

[00:00:50]And the reason these bulldozers were even available is one of those details that makes you stop and reread it twice.

[00:00:58]10 days before this, at exactly 11:37 p.m. on August 17th, 1959, a magnitude 7.5 earthquake hit the Madison River Canyon just outside [music] the western boundary of Yellowstone National Park.

[00:01:15]It lasted about 30 seconds.

[00:01:17]>> [music] >> And in those 30 seconds, the entire south wall of the canyon broke loose.

[00:01:23]37 to 43 million cubic yards of rock, schist, [music] gneiss, and dolomite sheared off the mountain, dropped into the canyon, and crossed the Madison River at roughly 100 miles per hour.

[00:01:37]The slide was 3/4 of a mile wide.

[00:01:40]>> [music] >> It climbed 430 feet up the opposite canyon wall.

[00:01:44]And it displaced so much air in that narrow canyon that the USGS [music] describes what came next as hurricane-force winds.

[00:01:54]Survivors said men were lifted off their feet. Cars tumbled end over end. Clothes were ripped off people standing in the open.

[00:02:04]Rock Creek Campground sat directly below the slide.

[00:02:08]50 campers were sleeping there. [music] Most of them never woke up.

[00:02:13]But upstream from the campground, in the overflow meadow and the higher camping areas, people did survive. [music] And what they went through in the next 18 hours is the part of this story that almost never gets told alongside the equipment.

[00:02:31]Mildred Green, who went [music] by Tootie, was a 30-year-old registered nurse from Billings camping with her husband Ray and their 9-year-old son Steve.

[00:02:41]They were on higher ground on a ledge between the river and the road.

[00:02:46]When the shaking stopped [music] and the roaring faded, Tootie could hear people screaming in the dark. She had just taken a first-aid refresher course. She had no medical supplies, no flashlight, no idea what had happened.

[00:03:01]She spent the entire night moving through the canyon in the dark treating injured campers with torn fabric and whatever she could find while aftershocks rolled through and the water kept rising below her.

[00:03:15]3/4 of a mile downstream, Grover and Lillian Malt, a retired couple from California, ages 71 and 68, had been sleeping in their house trailer near the river.

[00:03:28]The seiche wave from the lake sloshing over Hebgen Dam upstream ripped the trailer off its pad and swept them into the water.

[00:03:37]They found a tree.

[00:03:39]They climbed into it.

[00:03:40]And they held on for 7 hours in the dark, chest deep in water, with aftershocks shaking the branches, until someone found them at dawn.

[00:03:52]250 survivors ended up at a spot that would later be called Refuge Point, a slightly elevated area upstream from the slide. They had no communication.

[00:04:03]>> [music] >> The roads in and out of the canyon were destroyed. No one outside the canyon knew how many people were alive, how many were dead, or how fast the water was rising.

[00:04:14]They waited 18 hours.

[00:04:16]>> [music] >> We need to talk about the numbers people repeat about this event because the internet cannot get them straight.

[00:04:22][music] The magnitude.

[00:04:25]The visitor center signs and most books say 7.5.

[00:04:30]The USGS revised it to 7.3 in later publications.

[00:04:35]>> [music] >> The current official USGS earthquake catalog, using moment magnitude, lists it as 7.2. [music] All three numbers describe the same earthquake measured with improving instruments over 66 years.

[00:04:51]Anyone who tells you one of those numbers is wrong and another is right does not understand how seismic measurement works.

[00:04:59]They are all correct for their era.

[00:05:02]The slide volume is even worse.

[00:05:05]The signs at Earthquake Lake say 80 million tons.

[00:05:09]Wikipedia says 50 million cubic yards.

[00:05:13]The USGS Caldera Chronicles report from 2024, written by Mike Stickney at the Montana Bureau of Mines and Geology, uses 37 to 43 million cubic yards.

[00:05:27]That number comes from aerial photographs taken 5 days after the quake compared to a 1957 survey using a Kelsh plotter at 1 to 8,000 scale.

[00:05:38]It is the most precise measurement anyone has done.

[00:05:42]So, when we say this was the largest seismically triggered landslide in the recorded history of North America. We measured it.

[00:05:49]That is not a guess.

[00:05:51]And the earthquake did not just break a mountain.

[00:05:55]Inside Yellowstone, 289 hot springs erupted simultaneously.

[00:06:00]160 of them had no prior eruption record.

[00:06:04]>> [music] >> Sapphire Pool became a geyser throwing water 150 ft into the air.

[00:06:10]Old Faithful's eruption interval shifted permanently. Before the quake, it averaged about 62 minutes between eruptions.

[00:06:18]It has never gone back.

[00:06:20]Today, it averages around 93 minutes.

[00:06:24]One earthquake, one night, and the most famous geyser on Earth changed its schedule forever. [music] At dawn on August 18th, the first help arrived. Forest Service smokejumpers from Missoula parachuted into the canyon.

[00:06:39]Air Force helicopters began medevacing the seriously injured by midday.

[00:06:44]But the 250 people at Refuge Point still could not drive out.

[00:06:50]Highway 287 was cracked and collapsed in multiple places between them and the outside world.

[00:06:57]And then, late that afternoon, a single bulldozer appeared on the Hebgen Lake side of the canyon.

[00:07:05]It pushed rock and fill into the worst road collapses one section at a time until there was a rough surface wide enough for cars to crawl out.

[00:07:14]The operator's name does not appear in any USGS report, any Forest Service document, or any Army Corps record we could find.

[00:07:23]One person, one machine, 18 hours after the earthquake, built the road that got 250 people out of that canyon.

[00:07:32]And we do not know who it was.

[00:07:35]Like and subscribe [music] if you want to see what happened next.

[00:07:39]Because the slide was not the emergency.

[00:07:43]The slide was already over.

[00:07:45]The emergency was what was building behind it.

[00:07:49]The landslide had dammed the Madison River completely.

[00:07:53]Within 7 hours, water had risen 20 ft over the buried campground. Within 3 weeks, the new lake would be over 170 ft deep. But the rising lake was not the worst problem. 6 miles upstream sat Hebgen Dam, 85 ft tall.

[00:08:10]>> [music] >> It was built in 1915. It was holding 345,000 acre feet of water.

[00:08:16]That is four times the volume of the lake forming downstream.

[00:08:21]The earthquake cracked Hebgen Dam's concrete core wall from end to end.

[00:08:26]The upstream face settled 5 ft. And the seiches hit it hard.

[00:08:31]The lake sloshed back and forth and overtopped the dam four times in 11 hours. 3 to 4 ft of water pouring over the crest each cycle.

[00:08:41]If Hebgen Dam had failed, every drop of that water would have hit the landslide debris downstream, punched through it, and erased Ennis from the map.

[00:08:52]That is not our opinion.

[00:08:54]That is the conclusion of the Association of State Dam Safety Officials case study on this event.

[00:09:02]What saved Hebgen Dam was design redundancy, a concrete core wall inside an earth and rock fill shell that could deform without collapsing.

[00:09:12]The seiche peaks were each only seconds long.

[00:09:16]Seconds. The dam held by a margin measured in feet and minutes, not miles.

[00:09:22]So, when the Army Corps of Engineers arrived, they were not cleaning up after a disaster. They were racing to prevent a second one.

[00:09:31]On August 20th, 3 days after the earthquake, Major General Keith R.

[00:09:35]Barney, the Missouri River Division Engineer, flew in with his staff.

[00:09:41]He engaged Woodward-Clyde Sherard and Associates, one of the top dam engineering firms in the country, to assess both dams.

[00:09:50]The answer came back fast.

[00:09:52]Cut a spillway through the slide.

[00:09:55]Now.

[00:09:56]On August 22nd, Montana Governor J. Hugo Aronson formally requested federal emergency assistance.

[00:10:04]Lieutenant Colonel Walter Hogrefe took operational command on the ground.

[00:10:09]The Corps set up a project office in West Yellowstone.

[00:10:12]By August 24th, two bulldozers started cutting an access road to the top of the slide.

[00:10:18]By the 25th, that road was open.

[00:10:21]By the 27th, 23 dozers were on the debris, cutting a 250-ft wide channel.

[00:10:28]And here is where this story becomes a machinery vault story.

[00:10:33]The Anaconda Company copper mine in Butte, Montana, one of the largest open-pit operations in America, was shut down by a labor strike in August 1959.

[00:10:44]Butte is 3 hours from Madison Canyon.

[00:10:47]That strike idled every heavy machine and every experienced operator at the mine.

[00:10:53]D8s, D9s, draglines, and the men who ran them, all sitting at home.

[00:11:00]The USGS report states it plainly.

[00:11:03]Because the open-pit copper mine in Butte was on strike, an unusually large number of operators and equipment were available.

[00:11:11]Without [music] that strike, the Corps would have spent weeks sourcing machines from across multiple states.

[00:11:18]Instead, they had a full [music] fleet on site in 3 days. A labor dispute in a copper mine saved a town downstream from a lake [music] that should not exist.

[00:11:29]By early September, the operation [music] had peaked. 62 pieces of heavy equipment were on the slide.

[00:11:36]190 operators and mechanics ran 24-hour shifts.

[00:11:41]Five [music] portable gas engine lighting plants turned night into day on the debris field.

[00:11:48]The machines were the workhorses of the late 1950s Montana [music] construction scene.

[00:11:53]Period photographs show equipment consistent with Caterpillar D8s and D9s, [music] the largest civilian bulldozers in production that year, alongside crawler-mounted draglines in the Bucyrus-Erie class. [music] The Army Corps after-action report from September 1960 does [music] not list specific models.

[00:12:15]It simply says "dozers, tractors, and draglines."

[00:12:20]But if you have ever looked at a D8 radiator shroud, the photographs tell you what was up there.

[00:12:26]Like and subscribe. [music] We cover the equipment stories that history forgot.

[00:12:33]On September 10th, 23 days after the earthquake, water began flowing through the new 14-ft deep spillway. [music] Governor Aronson flew in for the ceremony, but the celebration was premature.

[00:12:46]The lower channel started eroding almost immediately.

[00:12:50]It had a 14% grade through loose, unconsolidated slide debris with water running over it.

[00:12:56]The engineers placed 100-ton [music] boulders as armor, but the water ripped them out. Nothing they put in the channel held.

[00:13:05]So, they changed the approach.

[00:13:07]Three large crawler draglines were brought onto the slide.

[00:13:11]Their job was to deepen the spillway by an additional 50 ft while water was already flowing through it.

[00:13:18]Think about what that means.

[00:13:20]Three operators sat in dragline cabs on unstable rock, swinging buckets into a channel with running water, pulling boulders and debris out of the current, while aftershocks as large as magnitude 6.5 rolled through the ground [music] beneath them.

[00:13:37]Each bucket load loosened the material around it. The water itself became a tool, scouring the channel as the draglines opened it up.

[00:13:47]They were not [music] fighting the river.

[00:13:50]They were using it.

[00:13:52]This went on for 7 weeks, >> [music] >> every day and every night under the lighting plants.

[00:13:58]On October 29th, 1959, 73 days after the earthquake, the spillway reached its final stable configuration.

[00:14:08]The total cost was $1.715 million, about $18 about $18 million in today's [music] money.

[00:14:17]And here is the line from the Army Corps after-action report that we have read three times and still do not fully believe.

[00:14:25]190 operators, 62 pieces of heavy equipment, 73 days of round-the-clock operations on the most unstable [music] ground in North America, aftershocks every day, a filling lake behind them, a cracked dam upstream, a town downstream, [music] and zero lost-time accidents. Not one operator was seriously injured. Not one machine was lost. On arguably the most dangerous earth-moving job in post-war American history, nobody got hurt. That spillway is still there.

[00:15:04]66 years later, it still controls the outflow of Earthquake Lake on the Madison River.

[00:15:10]But it almost failed. In June 1970, high water eroded the channel badly enough to damage Highway 287 downstream. Since then, Hebgen Dam operators have had to keep flow at the Kirby Ranch gauge below 3,500 cubic feet per second, specifically to protect the aging spillway from washing out.

[00:15:33]The bulldozers from 1959 are gone, but the cut they made needs constant management. [music] 66 years of it and counting.

[00:15:43]Earthquake Lake is 6 miles long and 125 feet deep. You can see it from Highway 287.

[00:15:52]The landslide debris field is still visible, 3/4 of a mile wide. The Earthquake Lake Visitor Center sits directly on top of it. At Cabin Creek, a 21-ft fault scarp from the earthquake still cuts through the ground. Near the upper end of the lake, the old Halford Camp cabins, lifted off their foundations by the rising water and deposited on a meadow when the spillway dropped the level, are still standing in the grass.

[00:16:20]Nobody lives in them.

[00:16:22]Nobody has since 1959.

[00:16:25]Dead trees still stand in the lake.

[00:16:28]Divers have found sections of the original 1959 highway, foundations of structures, and the remains of passenger vehicles on the bottom. And the 19 people who were buried under Rock Creek Campground on the night of August 17th, 1959, are still in the debris.

[00:16:47]220 feet below the surface.

[00:16:51]They have never been recovered.

[00:16:54]Every video about this earthquake tells you about the mountain that fell and the people who died underneath it.

[00:17:00]We wanted to tell you about the nurse who worked through the night without supplies, >> [music] >> the operator nobody can name who built the escape road at dawn, and the 190 men who drove onto that debris field 10 days later >> [music] >> and cut the channel that kept the river from taking a second town.

[00:17:20]If you know of another job where 190 operators ran 62 machines for 73 straight days without a single lost time accident, we want to hear about it.

[00:17:32]Tell us in the comments. Like and subscribe.

[00:17:36]We will see you on the next one.