40 years later: Scores killed in Big Thompson Flood

Editor's Note: On July 31, 1976, the skies opened up over the Big Thompson Canyon, setting off the deadliest natural disaster in Colorado history that claimed 144 lives and caused $35 million of damages. Read more in the Coloradoan's series about the details of the Big Thompson Flood, the aftermath and a look back at the news coverage 40 years ago.

A year's worth of rain fell in 70 minutes.

Clouds piled 12 miles into the mountain sky unleashed a deluge on July 31, 1976, setting off the most powerful flood since glaciers retreated 10,000 years ago.

The chaos along an otherwise trickling Big Thompson River killed 144 people, five of whom were never found, and carved out a chapter in the history books as Colorado's deadliest natural disaster.

It was the eve of the state's 100th birthday, part of a three-day shindig that drew weekend warriors and outdoor enthusiasts to the mountains of Larimer County. An estimated 3,500 people were camping, fishing and relaxing in the canyon that night.

40 YEAR LATER: Deadly Deluge: 1976 Big Thompson Flood

A thunderstorm parked near Estes Park and turned the sky a daunting black late that afternoon.

Some residents recall fishing in Loveland and looking to the west, curious about the strange storm pattern that didn't jibe with late-summer monsoon flows. Others remember the peculiarity of water filling wheel barrows in a matter of seconds or nature's brilliant light show after the sun set.

Even the 2013 disaster in the same spot paled in comparison both in body count and sheer brutality, largely because people were caught flat-footed some 40 years ago. A foot of rain fell during a few hours in a stretch of land between the tourist hub of Estes Park and the quaint mountain communities of Drake and Glen Haven.

With nowhere to go, that deluge sped down the rocky hillsides.

It took everything in its path.

"I'm stuck. I'm right in the middle of it. I can't get out..." said Colorado State Patrol Sgt. Willis Hugh Purdy in his last radio transmission before being swept away, killed by the water. He's credited with saving hundreds of lives by issuing evacuations lower in the canyon.

Propane tanks burst. Water buoyed homes. Babies were snatched from their families.

The river even moved a 275-ton boulder the size of a small house.

All told, the pressure washer of water that tore through the Big Thompson Canyon caused more than $35 million in damage to 418 homes and businesses — nearly $150 million by 2016 standards. More than 400 vehicles, many loaded with tourists or residents trying outrun the water, were swept off roads and sent crashing down the steep and craggy mountain canyon.

FROM THE ARCHIVES: A look back at Coloradoan's coverage of the 1976 flood

Bodies were pulled from debris piles and muck from high in the canyon to areas near Interstate 25. It wasn't until the death toll surpassed the 100 people that many realized just how bad this storm had been.

There were at least 250 reported injuries, and more than 800 people were helicoptered out when day broke and the sun shined the following Sunday morning, Aug. 1. The stories of survival, near death and loss made national headlines. Flood waters were replaced by a flood of people — rescuers, family members and journalists, their own stories making headlines about covering the mayhem in a time before cellphones, the internet and camera ubiquity.

"For days, it was a race from one stop to the next, then to the nearest phone or back to Fort Collins to make the deadline for the afternoon paper," wrote Jake Henshaw, the lead Coloradoan reporter who covered disaster, in a column marking the 10th anniversary. "...[W]hat strikes me most is not how quickly the flood and the rescue were over but how long the clean-up took and how deeply the scars cut."

10 YEARS LATER: Reporter remembers how Big Thompson Flood unfolded 

Families gathered at the old Loveland Memorial Hospital, anxious to hear the latest identity of the figures tucked in body bags, which were laid out in refrigerated trucks in the parking lot — there were too many for the morgue to handle. The bodies of five flood victims were never located.

Signs now dot U.S. Highway 34 — and canyons across Colorado — warning people to climb to safety in the event of flooding. That was a lesson from 1976. Flood plains were re-drawn. Some homes were rebuilt. Many weren't.

Each year, residents, friends, family, and survivors gather at the Big Thompson Canyon Association and Memorial Site, about one mile below Drake, 13 miles west of the Kmart on U.S. Highway 34 in Loveland. Sometimes there's singing. Other times just speeches. Scholarships to children have become part of the ceremony.

But there's always a somber note that hangs in the air, one that remembers the deadliest natural disaster in Colorado history.

WATCH: 1976 flood survivor tells his story

The five who were never found

Teresa Graham, 10, from the Cedar Cove area of the Big Thompson Canyon.

Evelyn Kindred, 67, from the Drake area of the Big Thompson Canyon.

George McCarty, 21, from Denver, was camping along U.S. Highway 36.

Vernon Oler, 51, from Longmont.

Rochelle Rogers, 2, from Brighton.

NEWS: How the Coloradoan covered the Big Thompson Flood in 1976

How the events unfolded 

5 p.m.Saturday July 31, 1976: Massive clouds erupt and light rain begins falling across the upper reaches of the Big Thompson Canyon.

6:30 p.m.: Rain turns heavy, particularly in areas between Estes Park, Glen Haven, and Drake along the U.S. Highway 34 corridor.

8 p.m.: People begin calling 911 to report rocks on the highway. A Colorado State Patrol trooper responds to investigate.

8:45 p.m.: The heaviest rain begins to fall, as much as a year’s worth in just an hour or two in many areas.

9 p.m.: Forecasters in Denver issue a weather bulletin warning of slow-moving thunderstorms that “could result in some local flooding.”

9:15 p.m.: Sgt. Willis Hugh Purdy, with Colorado State Patrol, radios his final transmission after warning dozens of people to get out of harm’s way. He would be among the dead pulled from rubble in the following days.

10:30 p.m.: A wave of water nearly 20 feet tall squeezes its way through the Big Thompson Canyon, destroying everything in its path.

11 p.m.: The National Weather Service issues its first flash-flood bulletin.

Sunday, Aug. 1: Death reports begin to mount. Rescue helicopters are mobilized, and daylight makes the destruction apparent. Days and weeks that followed would reveal 144 people perished in the flood that destroyed a canyon and changed lives forever.