Re-upping this post for July 31, 2026. The flood remains Colorado’s deadliest. Here’s a link to Coyote Gulch coverage mentioning the Big Thompson Flood.

July 31, 1976, Steamboat Springs: I had been wandering around the Flat Tops Wilderness for a week or so with Mrs. Gulch. Drizzle in between downpours during the monsoon. We were holed-up in a hotel to dry out and I phoned my mother to check in.

She asked, “Johnny are you anywhere near the Big Thompson Canyon? There’s been a terrible flood.”

And it was a terrible flood. After the September 2013 floods Allen Best wrote about being part of the disaster response in The Denver Post. It’s a good read on this 40th anniversary. Here’s one passage:

I was at the Big Thompson disaster. I was living in Fort Collins then and was among scores of young men (sorry, women, those were different times) with strong backs who could be summoned in case of forest fires. My only fire was at an old sawmill site in the foothills. The joke was that one of us had set the fire because we were so desperate for minimum-wage work.

Then came July 31. It was hot that night in Fort Collins. It hadn’t rained a drop.

I was living above Gene’s Tavern, just two blocks from the Larimer County Courthouse. When the call came, I was at the sheriff’s office almost immediately. It was 9 p.m.

Being among the first at the command center at the Dam Store west of Loveland, near the mouth of Big Thompson Canyon, I was assigned to a pickup dispatched to look for people in the water near the turnoff to Masonville. Already, the river was out of its banks. From the darkness emerged a figure, dripping and confused. “I went fishing at Horsetooth (Reservoir) and was driving home and then there was all this water,” he sputtered. He was befuddled. So were we.

Our leader decided we’d best get out of there. From what I saw the next morning, that was an excellent decision. Water later covered the road there, too. I spent the night at the Dam Store as the water rose. Helicopters were dispatched, but there was little that could be done. Our lights revealed picnic baskets, beach balls and propane bottles bobbing in the dark, roiling water that raced past us, but never any hands summoning help.

In the morning, we found those hands. The bodies were stripped of clothing and covered with mud. The first I saw was of a woman who we guessed was 18, not much younger than I was then. This thin margin between life and death was startling in my young eyes.

Eventually, 144 people were declared victims of the flooding that night (although one turned up alive in 2008 in Oklahoma).

Estes Park got some rain, but not all that much. The larger story was partway down the canyon, in the Glen Haven and Glen Comfort areas, where the thunderstorm hovered. In just a few hours, it dropped 10 to 14 inches of water.

Downstream in the canyon, just above the Narrows, some people were unaware that anything was amiss until they went outside their houses and saw the water rising in their yards. It hadn’t even rained there. One cabin I saw a few days later was stripped of doors and windows but stood on its foundations, a mound of mud 5 or 6 feet high in the interior. I seem to recall a dog barking as we approached, protecting that small part of the familiar in a world gone mad.

At the old hydroelectric plant where my family had once enjoyed Sunday picnics, the brick building had vanished. Only the turbines and concrete foundation remained. In a nearby tree, amid the branches maybe 10 or 15 feet off the ground, hung a lifeless body.

The river that night carried 32,000 cubic feet per second of water at the mouth of the canyon, near where I was stationed. It happened almost instantaneously — and then it was gone. It was a flash flood.

Here’s an excerpt from a look back forty years from Michelle Vendegna writing for the Longmont Times-Call.

Night on the ledge

“We, Terry Belair-Hassig and Connie Granath-Hays, graduated from Berthoud Jr. Sr. High School the month before, and were anxious to begin the summer. We spent the beautiful, sunny day of July 31, 1976, at a Hewlett-Packard company picnic at Hermit Park not far from Estes Park. After the picnic, we drove up to Estes Park and had dinner at Bob and Tony’s Pizza.

The clouds started moving in about 6 p.m., so we began the drive down to Loveland via U.S. 34. Within minutes, Connie had to pull her car over because the driving rain was causing zero visibility. We needed to get home, so she started out again, but we didn’t get too much farther before we were blocked by trees, boulders and debris washing down the canyon sides. We had just passed the Loveland Heights area — barely three miles since entering the canyon. The closest town, Drake, was miles away.

Connie pulled over to the side of the mountain as far as she could. There were a few other cars in this section doing the same, but we all sat in our cars — planning to wait out the storm. However, once the river began to rise and the water was hitting the tires, we decided to leave the car and start climbing. Connie’s dad had taught her to always ‘be prepared,’ so she had a tarp and a few extra jackets stored in her trunk. We grabbed them before climbing. It was a dark, treacherous climb.

A small group of people scrambled up the mountain near us. Connie gave one of the men her extra jacket. She also had a flashlight which came in handy later in the evening when the lightning wasn’t lighting up the canyon. The other people were lucky enough to find an overhang of rocks to sit under. We tentatively settled on a ledge out in the open, and wrapped ourselves in the tarp. Of course, the tarp was just an old tarp, not waterproof like the ones are today. It protected us for a while, but with the downpour of rain and runoff from the hillside, it too became drenched.

After only a little while, we watched her car, during the lightning flashes, being lifted up and carried down the river. We decided at this point we should climb higher, so we found a ledge where we spent the long, cold night. We had spent many winters skiing and had never been as cold as we were that night.

We sat on that little ledge (3 foot by 1 foot) with our knees drawn up to keep us from sliding off. We sang, shivered, cussed and did anything we could to keep our minds off of how cold and achy we were. We heard and saw cars, houses and propane tanks floating down the river during flashes of lightning. We thought by now it must be about morning time, but looking at our watch, it was about 10 p.m. We had a long night ahead of us.

The next morning was another blue bird day and we were freezing and soaked to the bone. We decided it would be warmer to take our jackets off and left them on the ledge. The road below us had been washed away, but the river had receded enough that we could get off the ledge and move around a little on the steep mountainside. We heard the helicopters for a long time before we saw one. Finally, we were rescued off the side of the mountain by a four-seat helicopter,and dropped off up river on a section of the highway that had survived. There were several other people there. I remember we were all surveying the canyon in a daze. There wasn’t much conversation. I leaned over and picked up a small piece of asphalt and put it in my pocket.

Click here to read the Fort Collins Coloradoan special about the flood.

From Wikipedia:

On July 31, 1976, during the celebration of Colorado’s centennial, the Big Thompson Canyon was the site of a devastating flash flood that swept down the steep and narrow canyon, claiming the lives of 143 people, 5 of whom were never found. This flood was triggered by a nearly stationary thunderstorm near the upper section of the canyon that dumped 300 millimeters (12 inches) of rain in less than 4 hours (more than 3/4 of the average annual rainfall for the area). Little rain fell over the lower section of the canyon, where many of the victims were.

Around 9 p.m., a wall of water more than 6 meters (20 ft) high raced down the canyon at about 6 m/s (14 mph), destroying 400 cars, 418 houses and 52 businesses and washing out most of U.S. Route 34. This flood was more than 4 times as strong as any in the 112-year record available in 1976, with a discharge of 1,000 cubic meters per second (35,000 ft³/s).

From The Greeley Tribune (Tyler Silvy):

Officials on Friday detailed how a Big Thompson River that was flowing at 30 cubic feet per second increased to 30,000 by the time it got to the narrows near Sylvan Ranch and the Dam Store.

The 2013 flood, by contrast was flowing at 16,000 cubic feet per second at the same point. But Bob Kimbrough, from the U.S. Geological Survey, said that number can be misleading. Just because it was flowing at less than half the rate, doesn’t mean the water was half as high as it was in 1976. It could have been a foot or two lower, Kimbrough said.

Further, the 2013 flood lasted longer. Where the 1976 flood dissipated nearly as quickly as it rose, the 2013 flood flowed over saturated ground for days, causing foundation failures and greater erosion than the 1976 flood.

Click here to read the extensive coverage from The Estes Park Trail-Gazette.