November 22, 2010 | On September 6, the Boulder County Communications Center received a radio call at about 10:00 a.m. of a fire in Fourmile Canyon. High winds helped spread the blaze, and within a week, 6,181 acres had been consumed along with 169 homes in what was the most expensive wildfire in Colorado’s history.
The fire affected UCAR/NCAR staff both personally and professionally. Two staff members lost their homes and a number were evacuated (see "When fire hits home"). Meanwhile, scientists in NESL/ACD used the fire as an opportunity to study a smoky atmosphere, EOL followed the action with radars and lidars, RAL provided the fire-fighting effort with high-resolution wind forecasts, and NESL/MMM continued its ongoing research on predicting a wildfire’s spread.
Giving forecasters a hand
Since 2009, RAL has been working with Xcel Energy to develop high-resolution wind forecasts to help the utility company integrate wind resources into Colorado’s power grid. The forecasting system incorporates output from a numerical weather prediction model, the Real-Time Four Dimensional Data Assimilation, and combines it with output from other models and weather observations made at wind farms. For this application, the RTFDDA has been optimized for wind forecasting, with 3-kilometer grid spacing that shows full terrain.
“With some of our people coming in overtime after the fire started, we were able to make changes in our operational data stream and export copies of images to a publicly available website,” David explains. “The material was then available to the National Weather Service staff who were supporting the fire effort.”
The customized forecasts, which were updated every three hours, included hourly maps of winds along the Front Range from roughly Denver to Cheyenne (see graphic) and forecasts of wind and other weather data for a point on Sunshine Canyon Road.
Sampling from the rooftop
The Fourmile Fire sent a plume of smoke over ACD’s chemistry labs in FL0, beckoning scientists to the roof to measure particles and gases. “As destructive as the event was, it also gave us a rare opportunity to learn more about fire emissions,” says Christine Wiedinmyer, who studies the role of wildfire emissions as air pollution.
The researchers used specialized instruments that can measure more than a dozen gases found in wildfire smoke, including methanol, formaldehyde, and carbon monoxide. They also took measurements to infer the quantity and size of particles in the emissions.
The data will help scientists better understand the impacts of wildfires on the atmosphere and climate as well as on human health. Recent research by Christine, Gabriele Pfister (also ACD), and colleagues has shown that wildfires can worsen air quality for thousands of miles downwind. In addition, the particles and gases in large-scale fires can influence climate by affecting the amount of sunlight that reaches Earth’s surface and by releasing carbon dioxide into the atmosphere.
Radar and lidar catch the action
When the Fourmile Fire broke out, researchers in EOL were testing the High Spectral Resolution Lidar, a new lidar (laser-based radar) built by the University of Wisconsin–Madison. The instrument, which is designed to fly on HIAPER, takes real-time vertical profiles of the atmosphere along a single line of sight up to 15 kilometers (9.3 miles) high, capturing cloud and aerosol particles.
During the fire, the lidar was in the FL1 parking lot, transmitting 24/7. The data output very clearly shows aerosols from the Fourmile Fire’s smoke plume (see graphic). “You can see two different types of particles: background aerosols and the smoke particles,” explains EOL’s Jothiram Vivekanandan.
When EOL’s Bill Brown saw smoke from his Gunbarrel home on the day the fire began, he rushed over to FL to turn on a developmental wind profiling radar. His EOL group, Integrated Sounding System, has two vertically pointing radars, one of which was already on.
The radars showed stronger-than-normal signals and falling motion. “I’m pretty sure that we were observing the ash and fine debris falling out of the smoke plume, as there was quite a lot of ash settling on cars,” says Bill, who’s done some research on radar observations of smoke debris from industrial fires. Another interesting observation, he says, was the height of the smoke plume, as the radars showed echoes up to 4 kilometers (2.5 miles) above the ground.
Predicting a wildfire’s spread
In MMM, meteorologist Janice Coen and colleagues are continuing their longtime research on coupled weather-wildland fire modeling, in hopes that it will one day be possible to issue fire forecasts with sufficient accuracy to aid evacuations and firefighting efforts.
Wildfires are driven by a combination of factors, including weather (especially winds and humidity), vegetation, and terrain. They are dangerous partly because of the seemingly random nature in which they spread, whipped by fast-shifting gusts of wind and flaring unexpectedly over fire lines into dry brush and trees. Factor in the usual uncertainties in weather prediction, and anticipating a fire’s movements is a daunting task.
Most recently, Janice used a model called CAWFE (Coupled Atmosphere-Wildland Fire Environment) to successfully simulate the 2006 Esperanza Fire, which killed five firefighters during a southern California Santa Ana wind event. The simulation, visualized with CISL's VAPOR software, captured fine-scale details well beyond Janice’s previous work, including the splitting of fire areas, flames drawn up canyons perpendicular to the spread of the main fire, rapid runs of flames along the flanks, fingers feathering at the fire’s leading edge, and particularly intense burning areas along the blaze’s sides.
“Wildfires are notoriously complex,” Janice says. “Accurately and reliably forecasting how they unfold would represent quite an accomplishment. There’s still a lot of work that needs to be done.”
“The most useful thing was listening to the police scanner, so for most of the day I was plugged into that,” Charlie recalls. “I knew that the fire was right below our house, and then on the scanner I heard reports that the fire was in my neighborhood and had crossed the road.”
Fortunately, nobody was home, as Charlie’s wife Debby was taking their youngest son to college. Their older son, Pierce, a student assistant in EOL, made it up to the house in time to rescue the dog, who was under the care of a petsitter, and grab a few photo albums.
Pierce later emailed Charlie a photo from Denver’s Channel 7 (KMGH-TV) of their home in flames. “It was one of the photos that had been on the front page of the Channel 7 website all day long, so we were sure our house was gone,” Charlie says. The garage survived, along with about half of the 34 houses in their neighborhood.
Charlie says that staff at McMurdo and NCAR were very understanding, and even offered to send him home early from Antarctica, which he declined. “I have an amazingly resilient family and my wife said she had a handle on things, so I decided I would stay and finish out the project,” he says. “I feel good that I didn’t rush home, because it really wouldn’t have helped anything.”
Charlie says that the thing he’ll miss the most are photos that were lost in the blaze. Debby's horticultural library with semi-rare books is another major loss.
Coincidentally, Debby is a fire scientist with the U.S. Geological Service, which undertakes studies after major wildfires. Her team plans to use the couple’s property as one of their case studies, documenting soil, vegetative, and other conditions. It is even collaborating with RAL’s Dave Gochis to study rainfall over the burned area.
“It sounded like a jet”
Dan Breed’s log home in Sunshine Canyon, which he built with his own hands in 1982, burned to the ground while his neighbor’s home 60 yards away escaped unscathed.
Dan and his wife, Diana, were both home when the fire started. “We could smell the smoke first, and then see the smoke,” he recalls. “The fire was a few miles away down below a ridge.” As neighbors gathered outside, Dan went inside for his camera. By the time he returned, he could see flames and hear the fire roar. “It sounded like a jet and you could see it gobbling up trees. It was pretty amazing.”
Dan and Diana had about an hour to gather their belongings before it was time to evacuate. In the chaos of trying to retrieve his neighbor’s cat, the startled animal bit Dan’s hand, ripping it open and sending the couple to the emergency room in the aftermath of the evacuation.
Dan has a philosophical approach to losing his home. “It’s just stuff,” he says, adding that seeing mementos in the rubble is sad. “But the memories are still there. It’s not like you burn down memories.”
He looks forward to having a chance to rebuild the house differently. “I think the rebuilding process could be exciting. It’s a chance to do things better than before. And it’s a nice area. It’s still a nice area.”
An ursine visitor
A number of staff were evacuated from the Fourmile region, and in some cases, fire wasn’t the only thing to threaten their homes. Terri Betancourt (RAL) was evacuated from her house in Lefthand Canyon for ten days. When she returned, relieved that her house was still standing, she walked inside to discover that a hungry bear had paid her a visit, leaving a giant mess of salsa, honey, butter, sour cream, cans, jars, and more.
“I just stood there and laughed at the absurdity,” Terri says. “I’d been worried about the place burning down. To come back to such a comical scene was a funny ending to what could have been a far worse outcome.”
Terri says that the bear had very particular eating habits, gobbling up cocoa powder but leaving tomatoes and potatoes untouched. It also came back for more, showing up on her property several times in the weeks after she returned. The bear sought not only food, but transportation as well, she says. “The next week, my car door was open on the driver’s side, and there were two spectacular bear prints on the front seat.”
A future of drought?
In an ominous note for wildfire potential, new research from NESL/CGD’s Aiguo Dai emphasizes the growing drought risk to the United States and other parts of the world over coming decades. Aiguo’s study, published in October in Wiley Interdisciplinary Reviews: Climate Change, concludes that warming temperatures associated with climate change will likely create increasingly dry conditions across much of the globe in the next 30 years, possibly reaching a scale in some regions by the end of the century that has rarely, if ever, been observed in modern times.
"We are facing the possibility of widespread drought in the coming decades, but this has yet to be fully recognized by both the public and the climate change research community," Dai says. "If the projections in this study come even close to being realized, the consequences for society worldwide will be enormous."
Aiguo used an ensemble of 22 computer climate models for the study and a comprehensive index of drought conditions, as well as analyses of previously published studies. For more about the study, read "Climate change: Drought may threaten much of globe within decades."