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Home / Articles / News / News /  Catastrophe: Boulder County
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Thursday, June 9,2011

Catastrophe: Boulder County

What natural disasters might we face?

By Boulder Weekly Staff

It`s been one hell of a spring. An earthquake, tsunami and nuclear crisis in Japan. Deadly tornadoes in Arkansas, Missouri and Massachusetts. Raging wildfires in Arizona and Texas. Floods from upstate New York to the Atchafalaya  River Basin. And last month, The National Oceanic and Atmospheric Administration (NOAA) issued its 2011 hurricane season forecast, predicting an above-average season of storms.

These events seem far away to most of us living on the Front Range. But what kind of danger might we face? And what can we do to be prepared? Boulder Weekly took up this issue, and what we found might contain a few surprises.

FLOODS

Likelihood: High

With annual precipitation averaging about 15 inches, Boulder seems more likely to suffer from drought than deluge. In 1894, however, a massive storm stalled over the foothills, dumping 60 hours of steady rain into an already swollen Boulder Creek. Parts of the town were transformed into islands. Present-day Canyon Boulevard was under eight feet of water, and residents were cut off from the outside world for five days. (The city even suffered a temporary “beer famine” as water cut the town in half, leaving the local brewery on the wrong side.)

This was the infamous “100-year flood,” so far the only one on record for the city. And while no one died in that flood, if a similar event happened today, the outcome could be quite different. Extensive development — a large portion of it on the Boulder Creek flood plain — combined with a much larger population means that a flood of that magnitude today could cause not only millions of dollars in damage, but also great loss of life.

The term “100-year flood” is more accurately described as a “1 percent flood,” meaning that in any given year, there is a 1 percent chance of it occurring.

(The term 100-year flood comes from the fact that over a period of one hundred years, you would — statistically speaking — expect to see one such flood) And the conditions would have to be just right: unusually high runoff from the mountains, caused by high temperatures melting a deeper-than-average snowpack, combined with a heavy storm system over the foothills. That scenario is far from impossible.

But even if Boulder County dodges the bullet again on a 100-year flood, residents still face an ever-present risk this flood season. According to Merrie Leach, emergency management coordinator at the Boulder Office of Emergency Management, as little as six inches of water can knock an adult down, and 12 to 18 inches is enough to float a vehicle.

An added risk to this year’s flood outlook is the burn area left by the Fourmile fire. According to Leach, because there is little to no vegetation in this area, as few as 1.7 inches of rain in an hour could cause rapid flooding.

Given that flooding is a matter of when, not if, the best thing you can do to keep yourself safe is be aware. If you notice unusually heavy rainfall or rising creek levels, get inside and seek information, either from the radio or websites like Boulder OEM. In addition, know your way to higher ground and get there on foot — not in your car. In the 1976 Big Thompson flood, of the 143 people who died, many were trapped in their vehicles.

DROUGHT

Likelihood: High

Drought is no stranger to Boulder County, in part because the term can apply to so many different conditions. A drought can be as short as a few months or as long as a decade, and there are a variety of drought types, depending on what it affects. For example, according to Matt Kelsch, a hydrologist with the University Corporation for Atmospheric Research, a “hydrologic drought” is one that affects residential, human consumption of water, while an “agricultural drought” is one that harms our local farms’ ability to grow crops. It’s also possible to have a human-induced drought, Kelsch says, “if we use more water than nature gives us.” And we could have overflowing mountain reservoirs and heavy snowpack to provide our Front Range cities with plenty of water, as we do this year, but still experience an agricultural drought on flatland farms after only a couple months of dry weather.

Climatologist Klaus Wolter of the University of Colorado and the National Oceanic and Atmospheric Administration says the last severe drought we had in parts of Colorado was between 1999 and 2002, a period that was followed by the devastating Hayman Fire. But that doesn’t necessarily mean drought always causes high fire danger, he adds.

“In the middle of a drought you could have low fire danger, if the humidity is high enough,” Wolter says.

One of the most severe droughts Colorado has seen was the Dust Bowl in the 1930s, which lasted about eight years. Kelsch says that while tree-ring data shows periods of 10-year droughts, those are rare.

He adds that while storm tracks play a major role in causing droughts, they can be self-inflicted by humans, who have built cities, planted trees and lawns, raised livestock and started farms, all of which combine to absorb vast amounts of water. About 80 percent of the West’s water is used for agriculture, he says.

“We like to create environments that are moist,” he says. “But I think people don’t take it seriously that we don’t have enough water for a long dry spell.”

Many local residents might equate drought with lawn-watering restrictions, but if we had a series of dry years, Kelsch says, we’d see strict water rationing, we would have to get our H 2 O piped or trucked in, and the price of it would go way up.

TORNADOES

Likelihood: Moderate

This spring there have been quite a number of tornadoes ripping through the area dubbed “tornado alley,” which includes Nebraska, Kansas, Oklahoma, Texas and parts of Colorado, Missouri and as far southeast as Alabama.

“Every time you have cold air coming from the north and you have warm and moist air coming from the Gulf of Mexico, and if the jet stream is at least five kilometers above sea level, these are conditions that are very favorable for tornado outbreaks,” says Katja Friedrich, an assistant professor in the University of Colorado’s atmospheric and oceanic sciences department. “This weather situation is very common from May until the end of June. That’s usually when most tornadoes will occur. Locally, the Front Range is where that usually happens.”

Friedrich says they chase tornadoes with mobile radar and use temperature measurements to calculate atmospheric conditions. But that doesn’t enable science to prevent the destruction and loss of life we’ve recently seen in Arkansas, Massachusetts and Missouri.

“We still do not have any predictors of when a tornado will form or if that tornado will be an F3, F4 or F5 tornado and how long it will last,” she says.

The largest tornado in the Boulder area occurred in 2008. It was an F3 tornado that touched down in Windsor, causing 78 injuries and one death. Although Weld County, where Windsor is situated, gets more tornadoes than any other county in the state, twisters are relatively rare in neighboring Boulder County. But that doesn’t mean a tornado couldn’t hit the county, particularly the eastern parts of the county, such as Longmont. (In fact, the Windsor tornado caused damage in Longmont, part of which was designated a FEMA zone.)

“Usually there aren’t any tornadoes in the mountains because you have very steep topography, so it’s very unlikely,” Friedrich says. “You have a lot of flow that gets disturbed. So it’s very unlikely to have tornadoes in the mountains, but they can actually occur in the foothills. So the further you go east, the more likely you will see a tornado. That’s why Boulder County is relatively safer than Denver.”

Friedrich and her colleagues continually study tornadoes to determine the atmospheric conditions around a tornado and what specific elements are necessary for a tornado to form. Scientists are still trying to solve mysteries around these twisters.

NUCLEAR CRISIS

Likelihood: Low

On March 11, a 9.0 undersea megathrust earthquake occurred off the east coast of Japan, causing widespread damage. One of the five most powerful earthquakes to occur during recorded history, it triggered a tsunami with waves that reached as high as 128 feet. The combined disasters brought about a third: an ongoing level 7 event at the Fukushima I Nuclear Power Plant, one of three nuclear reactors in Japan to suffer explosions due to hydrogen gas build-up caused by loss of power. Radioactive material was released into the air, reaching California in small but measurable amounts.

Attention quickly shifted from Japan to California, which is also prone to catastrophic quakes and tsunamis and which has nuclear power plants similar to those in Japan. Could an earthquake in California result in a nuclear catastrophe that affects us here in Colorado?

According to Jerry Peterson, a nuclear physicist at the University of Colorado at Boulder, the likelihood of any such thing happening are low.

“Our hazard is low for two reasons,” Peterson says. “One is containment. The U.S. reactors are all within very secure containment vessels. It turns out they weren’t designed this way, but they are even capable of withstanding aircraft collision.”

Although our oldest nuclear power plants are like those in Japan, Petersen says our procedures are different.

“One of the biggest problems in Japan is that the spent fuel, which is much, much more radioactive than original fuel, is stored in open pools,” he says.

“After five years, all of our power plants take it out and put into steel and concrete vessels. It’s much more protected.”

Japan’s current nuclear crisis was brought about by a compound electricity failure. The grid was down from the earthquake, and the tsunami knocked out the plant’s backup system, he says.

“As far as I know, our backup power is more reliable than theirs,” he says. “It’s safer from tsunamis. And we have a containment vessel even if the cooling fails.”

What about a nuclear meltdown such as that which occurred in Chernobyl?

Peterson says that disaster was brought about by human error.

“It was a whole bunch of things that were unique to the U.S.S.R.,” he says.

However, we should never assume we’re safe from everything.

“I could imagine a catastrophe that could do anything,” Peterson says. “You can never design a facility to withstand the absolute, ultimate disaster. … One of the very small prices we pay for the enormous convenience of electricity is that things can happen.”

EARTHQUAKES

Likelihood: Moderate

Part of what make natural disasters so dangerous is our inability to prepare for them. Most catastrophes are unlikely events — until they occur.

If any natural disaster has the potential to be Colorado’s equivalent of Hurricane Katrina, it’s a 6.5 to 7.25 earthquake centered beneath the Denver metro area.

According to the Colorado Geological Survey (CGS), more than 500 earthquakes have occurred in Colorado since 1867, the biggest of which happened on Nov. 7, 1882. Centered west of Fort Collins, the quake had an estimated magnitude of 6.6.

There are about 90 faults in Colorado that could be considered “potentially active,” according to the CGS. Although seismic activity in Colorado is low to moderate, the CGS warns that it is “prudent” to expect future quakes between 6.0 and 7.25 in magnitude here in our state. If a quake of that magnitude were to strike the Denver area, where a series of small quakes occurred in the 1960s and ’70s, damages are estimated to reach $10 billion.

“Scientists are unable to accurately predict when the next major earthquake will occur in Colorado, only that one will occur,” states the CGS.

Though the idea that Colorado might be hit by a major quake surprises most people, a glimpse at the Rocky Mountains, formed about 65 million years ago, is all it takes to remember that our landscape was shaped by seismic activity.

But at the moment, Colorado is quiet, seismically speaking, says Anne Sheehan, a geologist with the University of Colorado at Boulder.

GPS sensors are in place across the state monitoring the movement of the ground at our feet, and Sheehan says that movement, though detectable, is very small.

“Things are not pushing together in Colorado anymore,” Sheehan says. “Things are spreading apart very slowly. It’s less than a millimeter per year of extension. It’s on the order of 0.1 millimeters per year of extension.”

Sheehan says some of the quakes we’ve experienced in the state are the result of human activity. The 2.5-magnitude quakes that shivered through Denver in the 1960s and ’70s were centered around Rocky Mountain Arsenal.

“That was a chemical weapons plant that disposed of its waste underground using high pressure,” Sheehan says.

When the plant ceased doing that, the quakes stopped.

“There are a bunch [of small quakes] down near Trinidad, and they’re controversial — whether they’re related to coal-bed methane resource extraction or the disposal of water related to that or whether they’re natural,” she says.

CGS recommends incorporating “seismic safety provisions” in structures built in Colorado, as well as “earthquake monitoring, geological and geophysical research, and mitigation planning.”

VOLCANOES

Likelihood: Miniscule

A short time ago, geologically speak-ing, Colorado was a hotbed of some of the most spectacular and violent volcanic activity in the world, says G. Lang Farmer, geology professor at the University of Colorado Boulder. The most active region was found in southwestern Colorado around what is now the La Garita Caldera Complex.

“But that was 30 million years ago,” Lang says. “The party’s over now.”

And judging by the absolute lack of significant volcanic activity around the state, Coloradans can put to rest their fears of dying Pompei-style under a cloud of flaming ash. Volcanoes pose almost no threat to the state.

“You can never say [the risk is] zero,” Lang says. “But it’s pretty close.”

The most recent evidence of volcanic activity in Colorado is a dormant cinder cone volcano in Dotsero, Lang says. The cone is some 10,000 years old.

“You can’t really argue that it’s active, just that it’s really young,” Lang says. “If that thing exploded, people would come around and [watch] it. … It’s not dangerous.”

Of course, the closest, significant active geothermal feature to Boulder is the supervolcano under Yellowstone National Park, some 600 miles north. Four to six miles beneath the complex, ever-changing surface of our nation’s first national park lies a giant reservoir of magma, which is responsible for all the thermal features that make Yellowstone so popular.

Scientists at the Yellowstone Volcano Observatory closely monitor the thermal activity in the park, and Boulder geoscience consortium UNAVCO provides the observatory with GPS instruments for that purpose.

“The Yellowstone volcanic system produces a range of hazards, with severity increasing with rarity,” Christine Puskas, a data analysis with UNAVCO, said via email.

The Yellowstone supervolcano erupts one or two times per million years, Puskas said, and the last time it erupted, some 640,000 years ago, the cinder cone flung ash all over the western United States, from California to Texas. Boulder got about six inches of ash.

But never fear, for the odds are in our favor.

“Yellowstone is not currently considered to be building toward an eruption,” Puskas said.

ZOMBIE APOCALYPSE

Likelihood: Don’t lose sleep

Admit it. We all talk about it. We all make some sort of plan. We all pick a place to hold out and rattle off a list of weapons we would want within arm’s reach in case the city, state or nation is overrun with zombies.

Whether they’re the slow-moving zombies from Night of the Living Dead or AMC’s The Walking Dead or the super-fast moving zombies from 28 Days Later, we somehow have a plot of escape and defense. We have to survive for the sake of the human race.

But this is all fantasy, right? There’s no such thing as zombies, and there’s no virus that would make humans go crazy and want to eat each other’s brains. That’s what we thought — until the Center for Disease Control (CDC) posted a blog on its website for steps on how to prepare for a zombie apocalypse. The CDC announced that its Zombie Task Force is fully operational and ready.

“The Zombie Task Force is actually three members of the communications staff of CDC’s Office of Public Health Preparedness and Response,” says Maggie Silver, one of the three staff members. “So we’re charged with trying to educate the public on various preparedness methods, which was the purpose of the blog that we did.”

But when pressed for info on any past or recent zombie outbreaks that have been hidden from the public or any threats on the horizon, Silver came clean.

“To the CDC’s knowledge, there’s nothing out there that would actually turn someone into a zombie,” she says. “Hurricane season is about to get under way, and we’re really trying to come up with a way to raise more awareness for personal preparedness in general. We decided to take a different approach to what we normally do and spice up our message and use zombies as a metaphor for real disasters.”

We guess the CDC doesn’t really turn into an impenetrable fortress, either. What a disappointment. Still, it doesn’t hurt to be prepared, so check out the CDC’s website to see how to prepare to battle the undead: http://1.usa.gov/iwrJtF.

WILDFIRE

Likelihood: Inevitable

Wildfire danger is something we in Boulder County have become more familiar with over the past year, unfortunately. The Fourmile fire that erupted last Labor Day proved to be the most damaging in the state’s history in terms of property lost, and it was followed by several other conflagrations.

The dry March and April we had in Boulder County had officials worrying that we would be a tinderbox again, but the wet month of May helped address that fear.

Still, even a wet spring and early summer do not necessarily lead to decreased fire danger — in fact, the outcome can be the opposite.

“People shouldn’t overestimate how wet it’s been,” says NOAA’s Wolter. “It will only take a week or two to have high fire danger again. This is not a permanent recovery.”

Wolter says moist months in the spring and early summer give rise to lots of tall grasses, which can then dry out later in the year and become prime fire fuel, especially when the wind kicks up. He attributes the spate of wildfires that we’ve seen locally in the past year to that very phenomenon: lots of “fine fuel” caused by a wet spring and early summer.

“We’re sort of setting ourselves up again for a good crop of grasses,” he says.

Wolter adds that downed power lines are responsible for more wildfires than people may realize.

“Not all are started by lightning or by someone throwing away a cigarette,” he says.

When one thinks of preparing for a wildfire, the obvious precautions include replacing those old-fashioned wood shingles and trimming trees and bushes around one’s home. But cutting grass and weeds is just as important, Wolter says, noting that they dry out much more quickly than trees. If a fire is approaching one’s house, he says, one should hose down the entire structure with water if there is time.

The effects of wildfire, which we are experiencing now in the Fourmile area, include increased risk of flooding and erosion, since the vegetation and ground cover is no longer serving as soil stabilizer and sponge. As we have learned firsthand in the past year, in addition to short-term symptoms like the health problems caused by ash and smoke, wildfires can damage water quality, the local economy and property, not to mention the possible loss of life.

Still, naturally caused wildfires are part of earth’s biological cycle, and too much in the way of fire suppression can actually harm the health of a forest. Experts say fire can actually have advantages for plants and animals, in part because fires convert organic matter to mineral nutrients.

Respond: letters@boulderweekly.com

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