Why flooding on the Front Range is an inevitable disaster


Excuse my language, but: Holy. Shit. That's what all of us natural disaster-curious Internet voyeurs were thinking last week, our jaws giving in to gravity as we clicked through images from Colorado's Front Range of people trudging through baseball fields covered hip-high with water, roads sliced apart by whitewater, and cabins transformed into riverine islands. Weather Channel CEOs were, no doubt, rubbing their hands together and cackling, while the usually staid National Weather Service called the rains "biblical." "There’s no scientific definition of 'biblical,'" reported Climate Progress, "but the flooding has been unlike anything local residents have ever seen before."

Well, yes and no. The amount of rain that fell on communities like Boulder and Lyons was indeed historic, smashing those cities' monthly and daily precipitation records, and devastating many residents. In some locales, it's being called a 1,000-year rain event, meaning there's a 1 in 1,000 chance of such heavy rains in any given year. But it should come as no surprise that Boulder flooded. Crack open the history books and you'll find that the Front Range has always been flood prone. According to the Boulder Area Sustainability Information Network (BASIN), when it comes to flooding, "the Boulder Creek drainage is considered among the most hazardous in the entire western United States." The city sits smack at the mouth of Boulder Canyon, and because its floodplain is so developed, the risks to human safety and property are especially high here.

The Colorado National Guard responding last week to flooding in Boulder County, Colorado. Photo courtesy National Guard.

Boulder owes its vulnerability to geography. It's pushed up against the foothills of the Rocky Mountains and steep-sided canyons. When storms get stuck above it, as they did last week, rains can careen off pitched slopes into the canyons, where creeks swell and eventually burst forth onto the city itself. One of the earliest documented instances of this was in 1894, which incidentally, was also Boulder's last 100-year flood event.  Homes, bridges and train tracks were swept away, and the girth of Left Hand Creek apparently grew to a half-mile. Significant flood events have occurred more than a dozen times since.

J Dusheck
J Dusheck
Sep 16, 2013 01:11 PM
Great article, Sally! The quote from Olmstead says it all. I think it's interesting how reluctant people are to get out of their cars. Perhaps one reason is that so few people have ever hiked off a well developed trail or in the rain. So when the moment comes when they should get out of their cars and walk up a hill, they can't imagine what that would be like or if it would be more dangerous than sitting in a warm car.
J Dusheck
J Dusheck
Sep 16, 2013 01:14 PM
Please, forgive my error.
Colin  Holloway
Colin Holloway
Sep 16, 2013 01:14 PM
My sweetpea's son was awoken by my son's code, reverse 911, and then the sirens and then the skeedaddle.
He evacced to NoBo only to have that place go under and is now between the NoBo and central Boulder floods. Art work and bicycles at his apartment. Such is the life and concerns of a student.
Another friend in Lyons, his place is toast, sodden toast, that is. But he got his Martin out. Such is the life of a musician.
Friends of friends had it worse a pops with three kids and a home now downstream.

It is a heavy heart that sets my brain to flippant.
Here we are, again, in tragedy land.

And to think it could have been worse.

These days we can just reckon on the fact that the 100 year flood is now the Ten year flood.
Janet Kilby
Janet Kilby Subscriber
Sep 16, 2013 01:48 PM
Please cover the important story of fracking ponds overrun by flood waters and releasing unknown contaminants into our communities. As for ordinary flood damage, we are on high ground, but even so carpets and debris are pulled out of houses all along our street. I have friends who have been evacuated from Lyons, others whose homes were completely destroyed. Most have some kind of damage. It will take a long time for the community to recover.
Robb Cadwell
Robb Cadwell
Sep 16, 2013 07:53 PM
Chinooks and Hueys getting people out of the mountains all day as soon as the clouds lifted off, I think many places in the foothills won't have roads for quite a while. Boulder creek still moving right along.
Barbara & Frank Flocke
Barbara & Frank Flocke Subscriber
Sep 17, 2013 02:15 PM
Thank you for a nice article. However, it should be pointed out that Boulder has not been sitting on its hands waiting for the next event. The city has done a lot of flood management engineering over the last 30 or so years and some of it actually worked very well last week. I would go out on a limb and say that this helped prevent damage from turning out worse. Credit where credit is due.
Evan Ravitz
Evan Ravitz
Sep 17, 2013 02:37 PM
Don't forget "the Father of Floodplain Planning," the late great US Medal of Science laureate Gil White, who convinced Boulder and the world to keep people out of the floodplain! When I moved to Boulder in 1978 parts of Boulder Creek were channelized in concrete. If they hadn't restored it to near-natural condition, things would have been far worse. They removed an entire apartment building where I used to live at about 210 Arapahoe which would have been wiped out last week. Put the Creek Path, parks and parking lots in the flood path.
Jim & Arlene Wood
Jim & Arlene Wood Subscriber
Sep 17, 2013 02:55 PM
I am glad to have read this article before making too many generalizations based on my 43 years in Colorado and Manitou Springs. Even so, my memory says that from 1970-1990 most rain came from short thundershowers in the afternoon, between 3:00 and 4:00 PM. Patterns began to change in the 1990s, and prolonged storms in 1996 and 1999 flooded our basement. Re-landscaping our yards seemed to take care of the problem until this year, when we had not only the prolonged storms, but also brief, intense ones on the areas west of us that burned last year. The result has been flooding of a type we had not seen before. And when we saw the pictures of floating trailers in Greeley, and rampaging rivers in Longmont, I felt -- and still feel -- that what we were seeing was extraordinary, and was due to more than just geography.
Ann Meisel
Ann Meisel Subscriber
Sep 17, 2013 02:57 PM
The article offered some historical perspective but failed to challenge the process of city council and county commissioner selection/election regardless of background and interest. Check to see how many are tied to development--business and housing--and you will see more complexity to the issue. City planners can only recommend. County commissioners focus on elections.
     Additionally, more research would reveal the nature of the soils--gravel--and stone--usually softer granites on all of the Front Range canyons from the Cache La Poudre south. Add to that the water storage from lakes and dams for the Front Range and eastern Plains. It isn't just city and county planning.
Marvin Criswell
Marvin Criswell
Sep 17, 2013 04:31 PM
There was a flood in Pueblo in 1921 and another Front Range flood in 1965 as well. We were here for the 1976 Big Thompson flood, the 1982 Lawn Lake dam failure, the 1997 Fort Collins flood, and now this huge one - not since 1965 has the S. Platte flooded so far out in northeast Colorado. I have an official CoCoRAHS rain gauge. In SE Estes Park, we received 0.46" on Monday, 0.90" on Tuesday, 4.24" on Wednesday, and 3.82" on Thursday - 9.42" in four days. Fish Creek went from a gentle, silent flow, to a roaring dragon. It gobbled a large gap through Scott Ave. This time we had no water in our house. In 1997, the back yard filled up with water and the window wells were awash. Water ran in until the window wells were bailed during the downpour. We spent hours mopping up the mess in the basement. Afterward we learned that flooding is not just water that rises from a creek or river. It's any water that touches the ground before it affects your house. Water like that is not covered by home insurance. You need flood insurance even if you are nowhere near a floodplain.
Robert Krantz
Robert Krantz Subscriber
Sep 17, 2013 04:36 PM
Tragic. Even more so when you consider there is this thing called geology, that can rigorously delineate the degree and distribution of risk, either from modeling (rain fall into drainage areas, stream capacities and profiles, etc.) or from interpreting the geologic record that goes way back more than a few human life spans (flood plain and channel morphologies, flood deposits, etc.). Seems like too often geology gets replaced by engineering, which is dedicated to making what people want seem possible (towns in wrong places).
Serge Dedina
Serge Dedina
Sep 17, 2013 04:43 PM
As someone who has been spending a 2-3 weeks most summers up in Estes and the Front Range since 1987, it has been shocking to see the increase in development in the high country and on the Front Range, in areas that area essentially flood prone. I was always surprised to see homes literally at water's edge along the Poudre, and last year to see the impact of the fire around the Poudre. Additionally the impact of pine bark beetle related destruction of forests combined with fires and increased erosion, must play a significant role in increasing flood risk. But Dr. White would probably also be distressed by the amount of suburban development in floodplains throughout the front range. Can't even begin to fathom why so much flood-prone development was ever permitted.

Serge Dedina, Ph.D.
Executive Director
Author of: Wild Sea and Saving the Gray Whale
Buzz Burrell
Buzz Burrell
Sep 17, 2013 05:27 PM
Pardon me, but what's most inevitable is humans trying to explain the unpredictability of nature. A myriad number of natural disasters are "inevitable" at any given point on the planet.

Boulder probably does more flood planning - all kinds of planning - than almost any city on earth. That work is performed in a building that sits on Boulder Creek, right across from the Municipal Building where Council meets, and just downstream from the Library (which literally straddles the Creek) and the Justice Center (also directly on the Creek).

None of which were harmed this time, because rather than the expected quick deluge (like Big Thompson), this storm just sat on us and rained, and rained, and rained - "biblical" was a startling term for the National Weather Service to use, but it was the best way to describe it - 17" at my neighbors gauge, up from 12" total so far this year.

People like to either control nature or explain it. Environmentalists are as guilty as developers in this regard, and a bit more arrogant. Mother Nature however, doesn't care what you think. Not at all.

"Surprise is the nature of reality" - Buddhist saying.

Lisa Niermann
Lisa Niermann
Sep 17, 2013 08:14 PM
This is where I had to go to look for information about flooded wells on the front range.


Please try to cover this aspect of the flooding. Coloradans and all who have been forced to live with this dangerous industry deserve to know about the corporations that frack and drill, and how they handle their responsibilities during an event such as this.
Linda Hamilton
Linda Hamilton Subscriber
Sep 17, 2013 09:13 PM
Cally Carswell's article about flooding in the Front Range is very good-pertinent and interesting. Perhaps, it does not include all aspects of flooding perspectives or experiences that many of us think might be necessary to say. Her article started a great dialogue venue...all the comments contributed contain significant insights. Mine...haven't "we" always been maninipulating, managing, moving (not to forget...daming, fracking, storing, etc) our wonderful water from our fabulous western rivers? Maybe - again - Nature is wanting us to listen to her/him, whatever. Colorado seems to be getting a come-upance! Daggone it.
John Loll
John Loll
Sep 17, 2013 10:38 PM
Hey Cally and Everyone,

The recent rains have been called biblical in their impact, but a more complete and accurate description would be to cite global warming as a causal factor in their occurrence.

Below are findings from a recent study reported by the National Academy of Sciences which as summarized in the 9/21/13 of Science News says that:

"The summer monsoon that dumps rain on an otherwise-arid American Southwest may grow stronger as the climate warms, suggests a study of the region’s monsoon patterns of the last millennium. Across the Northern Hemisphere, monsoons — winds that change directions seasonally, altering rainfall — could intensify, the team reports May 27 in the Proceedings of the National Academy of Sciences.

The results complement recent observations and simulations of monsoon activity, says Pang-chi Hsu, a climate scientist at the University of Hawaii at Manoa, who was not involved in the work. 'We do see enhanced Northern Hemisphere monsoons over the recent decades, from the 1970s.'

In many regions, farmers and others depend on summer monsoons to deliver more than half the year’s rain. The researchers can’t say whether stronger monsoons will result in more water overall for these areas, says coauthor Yemane Asmerom, a geochemist at the University of New Mexico in Albuquerque. Warmer air holds more moisture, which leads to more rain. But, he says, warmer temperatures also increase evaporation in dry places such as the Southwest.

One outcome of stronger monsoons could be fewer but heavier fits of rain, which could unleash flash floods, says climate scientist Andy Turner of the University of Reading in England. But local factors will probably cause regional differences in monsoon. For example, he says, the concentration of soot and other aerosols or land surface features might weaken monsoons in some areas, offsetting some of the strengthening caused by warmer temperatures."

The link to the Science News article is here: http://www.sciencenews.org/[…]y_heat_up_with_the_climate. Apologies to all for not knowing how to hyper link to the site.

My prayers and well wishes go out to all impacted by the floods.

Cally Carswell
Cally Carswell Subscriber
Sep 18, 2013 08:28 AM
Thanks for all of your thoughtful comments. As Linda points out, this is a short blog that could not and did not set out to cover all of the important aspects of the floods. There are certainly many more stories to tell and questions to ask. John, while it is true that the summer monsoon could become stronger in a warming world, from what I understand from climate scientists working in the Southwest, that's still an area of substantial uncertainty. Also, I don't *think* these recent storms were part of the summer monsoon patterns, which I *believe* tapered off in August. (Someone correct me if I'm wrong.) Certainly the risk of more severe storms is heightened by climate change, and for that reason, these storms could serve as a cautionary tale. They can't be decisively blamed on climate change, though, just like any other single weather event. For an excellent analysis and explanation of the floods' ties to the changing climate, see this Climate Central story: http://www.climatecentral.o[…]nnual-rainfall-record-16481
Michael Kopp
Michael Kopp
Sep 18, 2013 09:05 AM
Cally, my understanding of the cause of the storm is that it was a combination of strong but otherwise typical monsoonal moisture flows (which have usually stopped by this time of year, but didn't in this instance) coupled with an extremely slow-moving and potent upslope storm.

Also, while you are correct that Boulder is flood-prone and knew, or should have known, the risks of flooding, it is also true that most flood forecasters thought the next big flood would come from a combination of heavy rains and melting snow and would be more or less confined to existing floodplains. If that kind of flood had happened, I wouldn't have as much sympathy for those who built or bought in the 100-year floodplain, knowing the risks. But this flood was different. It was caused by unprecedented rainfall that was distributed over a wide area, causing flooding in areas that are nowhere near a normal floodplain. Basically, anyone who had higher ground above them was at risk of flooding, even if they were well away from Boulder Creek and other existing waterways. An area near my home, located on top of a high ridge, flooded terribly. Before this, I never would have expected it to flood even in a 1000-year flood event. But water from even higher areas swept through and damaged or destroyed many homes.

Also, Boulder may be flood-prone, but there's hardly anywhere in this country (plant, universe) that isn't especially prone to some kind of natural disaster: hurricanes (Eastern Seaboard), tornadoes (the South, Great Plains, Midwest), drought (Southwest and West), forest fires (West), earthquakes (West Coast), volcanic eruptions (Northwest), and on and on. Chiming in after a disaster strikes to say "gee, you should have known better than to stick a city there" may be correct in some ways, but its also not particularly helpful. People have to live somewhere.
John Loll
John Loll
Sep 18, 2013 06:17 PM
Cally and Everyone,

Cally thanks for your comments, but I do believe there's a relationship, but I also acknowledge that judging the extent of the role of climate change is problematic. For yet another view, I'd refer folk's to a Democracy Now! video that discusses some of the issues around how climate change may have impacted the recent floods. Bill McKibben's comments are especially relevant in my view.

Link to: http://www.democracynow.org/[…]/the_1_000_year_flood_did
Also, warming temperatures may be affecting the movement of storm systems across the US causing storms to 'sit' over locations as pressure ridges block their movement. Go to the Climate Central or Climate Progress websites to learn more. I distinctly remember reading about this consequence. Finally, I want to make clear that I'm a lay-person trying to understand this rapidly changing world around me with no special training or pedigree in these matters. But I do find it amazing that there was not one mention by major media concerning climate change in relationship to the floods according to Amy Goodman.

Heather Hansen
Heather Hansen
Sep 19, 2013 10:49 AM
Flooding of the type Frederick Law Olmsted, Jr. wrote about was, of course, expected. There are high risk areas that resonate outward from Boulder Creek where federal flood insurance is mandated. The Natural Hazards Center at CU even has a template on its website (created by the great pioneer in flood plain management, Gilbert White) for such an event with blanks to be filled in for number of lives lost, structures lost, costs incurred. Surges in excess of 10,000 cubic feet/second (200 times the normal flow this time of year) have been predicted. In the past century, mitigation efforts have been made and many proved effective during this event.

The thing is, last week’s flooding does not remotely fit the usual pattern of high water here. We anticipate floods on the Front Range in spring or during the monsoon when intense storms can deposit copious rain in confined areas (such as during the cited Ft Collins and Big Thompson events). We have been warned about the increased danger when these events collide with a drought-stricken and/or fire-scarred area. What just happened, however, was a completely new kind of event which I’ve heard scientists (some of whom live and work on the Front Range) refer to as ‘bad luck’, about as expected as a meteor flattening us.

Boulder gets roughly 1.5 inches of rain each September. Our previous record set nearly 75 years ago was 5.5 inches. In North Boulder we got over 21 inches of rain from this one rain event. Before the storm, Boulder Creek was running at 54 cfs; during the deluge it reached 5,000 cfs. Near where I live the hillsides dropped away in wide swaths and ditches and ‘dry’ creek beds exploded with runoff that is marked on not a single flood hazard map. Roads and homes were overcome, as was our understanding of the familiar.

This event was not “inevitable.” There is no precedent for flooding of this severity and magnitude in 17 counties covering some 4,500 square miles. It may make us feeling less afraid, or perhaps superior, to say that we expected this all along but it’s just not so. Have we grown wiser in the past week? I like to hope so but humans, myself included, are notoriously short-sighted. We’re also sentimental; it would be very comforting and convenient for me to believe that climate change will not increase the likelihood of this happening again (and that my property and lifestyle are not imperiled) but we have to recalibrate for a new normal. And, at least next time, we can say we saw it coming.

~Heather Hansen
Charles Watkins
Charles Watkins
Sep 20, 2013 09:33 AM
Cally et. al.
I love the fact that High Country News provides a place for westerners to gather, discuss and debate the issues of the day. Thanks for that. I, no doubt, am probably joined by many here in extending our gratitude.

This article however, albiet an intentionally short blog post, amounts to as much as those of us who, when spotting a fire truck on the highway, shake our neighbors and scream, "Look, a Firetruck!" Well, to that I say, "Duh. Big, Red Truck."

For anyone who has ever trampled around Colorado's dessicated westside, Utah's magnificent interior or Wyoming's hardscrabble western regions (and truly the list goes on), the effects of floods have made themselves known to all of us before. Just because we haven't been around long enough to record their devastations with our own eyes, does not negate their lingering and latent presence. Today, dried out orollos make for excellent Mountain Biking in Fruita, yesteryear they were momentary boiling torrents of muddy tragedy (had there been a farm there... and for all we know maybe there was one there in 1630).

My point is thus: we live on Earth. Earth is, was, and always will be a tempestuous "neighbor." She is not bound by our presence to record her actions, predict her actions, anticipate her actions, plan for (or not) her actions. She is, as she does. I contend that it's un-truthful to seek, attribute and fervently affix blame to our most recent tragedy. Nature threw Colorado's front range (and New Mexico and Nebraska for that matter) a screw ball that nobody could have or did see coming. That sucks (especially for those directly affected), but it HAS to be OK. I say it 'HAS to be OK' because nature will do it again. And again. Fires will ignite. Soils will erode. Rain will fall. No doubt, there is a blizzard in our collective future - as well as their corresponding heavy snowmelts.

What was supposed to be a damp September Friday, turned into a slow storm that was cornered, wet and well fed from the Gulf's continual input. Unique conditions that came together and presented us with new challenges to see the world for what it is - rather than what we must see in order to confirm our biases.

Craig Jones
Craig Jones Subscriber
Sep 23, 2013 04:43 PM
A couple quick points. This was NOT a "1000 year flood" [outside perhaps some small creeks]--it was a 1000 year rain. And outside of the tremendous sheet flow over areas that saw the huge rain (a region extending from Boulder to the northwest) the flooding isn't quite as unprecedented as it might seem. This is not the biggest flood disaster in Colorado history: the 1965 flood was worse (~$4B vs ~$2B). It is not the only September flood of note (in 1938, Eldorado Springs ended its run as a major resort owing to a similar flood).

Perhaps surprisingly, this wasn't even a 100 year flood in Boulder's downtown. While Salina and other areas off Fourmile Creek were trampled, water didn't rise nearly so much in the main Boulder Creek. Farther east, where the waters that fell on smaller streams collected into Boulder Creek, things progressed to perhaps a flood of once in 100 year average. Arguably this event was more damaging to Boulder households than any 100 year or 500 year flood simply because you didn't need to get a creek rising into your basement, you just needed a little negative drainage right under a downspout. So Boulder's geography actually played little role in damage here (a different story in Lyons and points downstream, where the rain fell more heavily to the west, engorging both forks of the St. Vrain). The kind of flood that Boulder planners feared didn't quite happen (heavy rain on a big snowpack barreling down the canyon).

Why bring this up? There are lessons to be learned but only if we understand what this really represents. There is a risk that some might see the fact that downtown Boulder came through nearly untouched by Boulder Creek as indicating that flood planning was a success and no more mitigation is needed. Considerable housing was just barely spared near the university and arguably needs to be removed from the floodplain. More rain up Boulder Creek's main stem might have made for a different story...Saying this was Boulder's 100 year type flood is misleading. Conversely, large parts of town had street damage and basement flooding that would never have problems in a classic hundred year flood; protecting those areas against another 1000 year rain might make no sense.

Another thing worth examining is that a fair part of the flooded subdivisions in Longmont were out of the *500* year floodplain, yet the St. Vrain blew through some of these with a vengeance while staying inside the 500 year floodplain to the south. It appears that a series of old gravel pits helped out, but this suggests that some of the floodplain maps are inadequate and not properly accounting for some of the changes to the landscape made over the years or the dynamic nature of riverflow in a flood (rivers don't simply fill up to some bathtub level, they will erode and redeposit sediment in response to obstacles).

Finally, something I have seen no mention of has been the role of irrigation ditches in house flooding. The headgates on these ditches were overtopped and large flows of water went down these channels, often through backyards. I've seen some properties damaged that would have had no problems had the ditches not filled and overflowed. You can speculate on whether this puts a ditch company at fault in any way....

Sorry, not as short as I thought when I started...
Craig Jones
Craig Jones Subscriber
Sep 23, 2013 04:44 PM
PS--I had to leave out some useful URLs as the anti-spam service was too stupid to recognize useful URLs from commercial spam.
Cally Carswell
Cally Carswell Subscriber
Sep 24, 2013 05:04 PM
Thanks, Craig, the reference to "1,000-year flood" has been corrected to "1,000-year rain event" with a link to NOAA's maps.