The floodwaters have largely receded, and the lists of unaccounted for people have dwindled.
In their wake, they’ve left hundreds of miles of destroyed highway, dozens of washed-away bridges, and thousands of demolished and damaged homes.
The rebuilding process that Colorado faces now is a daunting, hugely expensive task that will ultimately take years. It is also, say many disaster experts, an opportunity – a chance to rebuild some things better than they were before, with an eye toward withstanding future flooding.
“The silver lining with events like this is you do have the opportunity to redo things differently – the layout of roads, the layout of towns,” says Michael Gooseff, a professor of hydroecologic science and engineering at Colorado State University in Fort Collins. “Mother Nature has reset the playing field for us.”
The competing goals of speed, economy, and disaster mitigation and planning can sometimes be at odds with each other, experts say. And simply the scale of what needs to take place is daunting. But Colorado Gov. John Hickenlooper and Jerre Stead, his new chief recovery officer, have talked about rebuilding “stronger” – though the governor has also set a relatively rapid target schedule.
Preliminary estimates say that some 200 miles of highway and about 50 bridges have been wiped out or severely damaged, and more than 2,000 homes destroyed. Many of those roads go through challenging mountain terrain and are vital to connecting communities, now largely isolated.
"We are about to embark on a rebuilding effort that is truly epic in scale," Governor Hickenlooper said at a news conference last week, in which he set a Dec. 1 deadline for rebuilding as many roads and bridges as possible. "We want to recover and rebuild quickly, better, and in the most efficient way possible."
In many ways, the task Colorado now faces is similar to that facing Vermont after hurricane Irene hit two years ago. Like Colorado, Vermont is a mountainous state, and the deluge of rain that fell poured into narrow valleys, washing away roads and bridges. The state lost some 500 miles of roadway and more than 30 bridges.
“The kind of flooding we had, and that Colorado is experiencing, is erosion, tremendous erosion. The power of the water just ripped apart roads, bridges, and many many homes and businesses,” says Sue Minter, deputy secretary at Vermont’s Agency of Transportation.
And, just as in Colorado, Vermont faced the prospect of a looming winter season when construction is largely forced to a halt.
Ms. Minter was part of a delegation from Vermont that flew to Colorado shortly after the flood to share some of what they’ve learned with their Colorado counterparts. One of the suggestions, according to Minter: Having an “incident command system” in place to allow for the quick marshaling of resources was hugely helpful, says Minter, who says Colorado is already moving toward a similar structure.
Vermont also reached out to the federal government and to neighboring states for help, and did whatever was possible to get roads replaced quickly, before the onset of winter, and to expedite permitting processes.
But that goal of speed, notes Minter, doesn’t have to be at odds with careful planning. Her advice to Colorado officials: Do everything possible in the short term simply to get roads passable. Then, once the winter has passed, take a closer look at all the projects with an eye toward rebuilding for resilience, to withstand future disasters.
“In this moment, they need to get those roads up,” says Minter. “But then they need to go back and think long-term.”
Once winter had passed in Vermont, a team of people that included both transportation officials and scientists revisited more than 600 sites to evaluate their strength, and ultimately concluded that about half of them needed more rebuilding, or repositioning, to make them stronger. Details like the contour of the road, and how it’s sloped near the river, can matter hugely when it comes to flooding, says Minter.
Some of the questions facing Colorado communities will include what sort of future disaster to plan for.
Weather experts are calling the rainfall and timing of the recent storm a “thousand-year storm.” The flooding, on the other hand, was more in line with a 100- or even 50-year flood, depending on the spot. But as extreme weather events occur with more frequency around the globe, some geologists say the accuracy of relying on past data to predict future events is in doubt.
“If this has a 0.1 percent chance of happening, one could say I’m going to take my chances, it’s very unlikely this is going to happen again even in the next 100 years,” says Mr. Gooseff. “But I’m starting to wonder if … we’re moving into this new regimen, where the next 100 years won’t look like the last 100 years, and we can’t rely on old records.”
Gooseff says that while there’s been a lot of focus on speed of rebuilding, he’d like to see more attention and discussion about doing it wisely. East of the mountains, for instance, towns like Evans and Sterling also flooded badly, not with flash floods coming down canyons but just with a huge overflow of water. Trailer parks in some places were almost completely destroyed, and people who had little to begin with lost nearly everything. Resettling some of those parks in the same spot may not be the wisest move, says Gooseff.
Boulder, the epicenter of much of the rainfall, actually had relatively little damage compared with some surrounding communities, like Lyons and Longmont – which many attribute to the stringent flood planning the town had in place.
In recent years, bridges across Boulder Creek were made higher and stronger. Bike paths were strategically situated to prevent some development right along the creek, and to serve as an outlet for flood waters. The town put in place a more stringent mapping system than was required, put in place a good warning system and storm water management program, and went above the minimum federal standards for flood planning.
The result: While hundreds of homes and businesses in Boulder were damaged or destroyed, the city didn’t lose a single bridge, its water remained safe to drink throughout the flooding, and no deaths occurred in the city of Boulder itself.
“Boulder has done a lot of good things” on flood planning, “above and beyond the call of duty,” says Clancy Philipsborn, a retired disaster recovery consultant from Boulder.
But he and others say tough decisions are ahead for many communities, especially ones like tiny Jamestown, in the foothills northwest of Boulder, and Lyons, a small town at the bottom of the foothills where the St. Vrain River emerges from canyons.
Both towns were largely wiped out, and the rivers completely rerouted. Do they rebuild as they were before? Do they keep the new path of the river or try to put it back where it was? Are there some places that simply aren’t a good site for structures, or for roads? If roads are rebuilt in those spots, should they be designed to simply wash away again?
“Every decision is tough,” says Mr. Philipsborn, who would like to see planning rather than speed take priority. “This is the exact time when regulations are needed,” he says. “If you waive those rules, you open yourself up to seeing repetitive damage in the future.”
The aftermath of disasters can be a time when people are willing to pay attention to hazard experts that they ignore at other times.
When the Lawn Lake Dam failed in 1982, flooding the mountain town of Estes Park (which was flooded again this month), the town used it as an opportunity to brush the dust off an urban renewal plan for the town’s rebuilding. There was federal money available, and a chance to start from scratch with some of the planning – including reducing the number of bridges, most of which had been washed away.
“They said, we can think forward, do the things which we’d thought about but didn’t have political clout or money for until we had the flood,” says Eve Gruntfest, a retired geography professor from the University of Colorado in Colorado Springs whose research has focused on flash flood warnings since the 1976 Big Thompson flood.
But sometimes even the best planning fails.
One of the roads that was badly hit by the flood was US Highway 34, which connects Loveland and Estes Park through the Big Thompson Canyon. The road was rebuilt after the deadly 1976 Big Thompson flood – still the deadliest flood in Colorado, claiming nearly 150 lives – supposedly to withstand a future flood. But according to the Colorado Department of Transportation, 85 percent of the highway was again destroyed when the Big Thompson flooded this time.
“Seeing the narrows – I almost didn’t believe it,” says Ms. Gruntfest. “We didn’t think in our lifetime we would see it again.”