Academics and officials are observing 50 years since a massive flash flood tore through Big Thompson Canyon between Estes Park and Loveland. A July 31, 1976 storm dumped over a foot of rain on the area, killing 144 people.
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Neil Grigg is a civil and environmental engineering professor at Colorado State University. He told KUNC monsoon rains brought the flood on fast and many people were caught off guard.
“In 1976, we had a convergence of this high level of rainfall, and it happened to drop at the wrong place, which was at Estes Park,” Grigg said. “It fell on rocky and steep slope soils, and it was almost like a bathtub effect, where so much rainfall ran off so quickly down the Big Thompson Canyon, and at the time, people were not really aware of this flood risk.”
The state’s historic flooding events have taught lessons and inspired advancements in engineering, infrastructure, and warning systems to improve flood management, including the 1965 flood of the South Platte River over a decade before Big Thompson.
“It was a similar situation,” Grigg said, “but it was more property damage than it was loss of life. The one that came down to Big Thompson Canyon in 1976 was a flash flood that was in such a narrow canyon that the loss of life was a lot greater.”
Lori Hodges, director of Larimer County's Office of Emergency Management, told Erin O'Toole on KUNC’s In The NoCo disaster warnings have a much broader reach these days.
“In 1976, obviously there were no cell phones, there was no texting, there was no social media, and so they really had a limited number of ways to get information,“ Hodges said.
Some National Weather Service systems didn't exist in the Big Thompson watershed at the time of the flood.
“It was in a bubble where you had all this stuff around it, but it didn't really have the systems in place technologically to help it,” said Hodges.
Hodges told In The NoCo she thinks about the flood - and its lessons - often, including during recent emergency planning drills.
“Practice for a flood like the Big Thompson flood is important because of how large of an event it is and how many people it impacts and the number of systems that we also use that could be challenged or could fail during one of those events,” Hodges said. “Even if it's not technology, it could be a system of coordination, so we want to make sure that our people know each other before a disaster, that they're talking to one another, that they're working through plans together, and how we're going to coordinate.”
Floods in Fort Collins in 1997 and back in the Big Thompson area in 2013 both had single-digit death tolls because of advancements in weather forecasting and hydrologic predictions.
“That doesn't mean that we're not going to have more disasters, because we're going to,” Grigg said, “but the challenge here is not nearly as much as it would be in areas that lack the kind of protection that we have.”
For the anniversary, Colorado State University has released a remembrance of the late forensic anthropologist Michael Charney, a CSU professor who led the efforts to identify recovered bodies. Charney’s expertise in skeletal remains helped advance the field of disaster victim identification.
The Loveland Museum opens an exhibit marking the 50th anniversary of the Big Thompson Flood from Friday, July 31 to Saturday, November 28, 2026.
