Tom Veblen, a professor emeritus of geography at the University of Colorado Boulder, saw smoke in Boulder’s air on Dec. 30 and decided to walk up a trail close to his home to investigate. Veblen, a professor of geography at the University of Colorado Boulder, claimed he could see the Marshall Fire, which was located on the southern edge of Boulder, jumping over several hundred yards.
The wind gusts were so strong that he had difficulty opening his car door and keeping his feet on the ground during the strong gusts. As winds gusted over 100 mph, the wooden fences that separated yards in suburbs were blown away, igniting roofs, decks and residential landscaping, they looked like burning fuses. The firestorm would eventually consume shopping malls and a hotel.
Veblen felt a strange sense of vulnerability as a resident in a neighborhood he believed was safe from the fire-prone forest.
“Sure, I knew that Chinook winds could drive winter grassland fires to spread very rapidly, but in the past we just did not have all the driving factors align so perfectly—wet spring producing abundant grass fuels, one of the warmest and driest June-Decembers on record and then an ignition at the base of the mountains.” Local topography also contributed to the intensity, with a canyon opposite the fire acting like a nozzle, blasting winds from the peaks onto the flames and pushing the fire east into suburban neighborhoods.
The Marshall Fire ultimately burned some 6,200 acres, destroying at least 1084 homes and seven commercial structures, before it was largely smothered by a New Year’s Eve snowfall. Investigators reported Wednesday that partial human remains were found, which they believe to be the remains of one of two people still missing from the fire. Insured losses are estimated at about $1 billion, making it Colorado’s most destructive fire on record in terms of property loss.
In the days since the fire, Veblen said he’s had many conversations with neighbors and friends, some feeling a combination of survivor’s guilt and post traumatic stress disorder, and all wondering how worried they should be about wildfires burning into suburbia in the future.
“I told them that, this winter, we’re probably going to be OK,” he said. With the shortening of the snow season and the desiccating grasses each year, there are more chances that the same drought, heat, wind and heat will align more often to create wildfires in the cold seasons and develop landscapes once thought to be rare.
In the meantime, few residents of rapidly expanding suburbs in which most of the vegetation has been planted by homeowners and developers realize that they are living in an expanding “Wildland Urban Interface,” or WUI, in which wildfires can threaten their homes and lives. In areas without natural vegetation, wooden fences, decks, wood frames, flammable roofing, and landscaping can provide fuel. They can burn down into glowing chunks when high winds blow them up, helping to lighten the fires.
“We could have another fire starting in Sunshine Canyon in some of those grassy areas and burn right down into Boulder,” he said. “We could call it a freak event, but we know that it’s not. It’s just a matter of those conditions setting up again.”
President Biden, Colorado governor, visited the Marshall Fire-ravaged communities Friday. He said that Jared Polis (D-Boulder) and Rep. Joe Neguse, (D-Boulder), could help to jump-start the discussions needed to address this threat.
“The important message our society needs to hear from them is that this is an example of a climate-enabled event, and the probability of similar events will continue to increase as we have continued warming,” he said. “Unless we keep fossil fuels in the ground, these events are going to get more frequent and worse.”
New Climate, New Fuels, and New Fires
“It’s clear the climate change is increasing the likelihood of these types of events,” said University of Montana fire ecologist Phil HigueraCurrently, he is a visiting fellow at Cooperative Institute for Research in Environmental SciencesBoulder, University of Colorado. Studying the relative impact of climate, vegetation, and human activity on wildfire trends.
“What I don’t want to see is a reaction of, ‘Oh, this is such an extreme event that we can’t do anything about it,’” he said. “Yes, this fire was very bad luck, but we shouldn’t be rolling the dice with fire in December.”
Global warming is causing more fires, according to research. This includes a landmark 2019 study on fire weather indices. Warmer temperatures, decreasing precipitation, and increasing heat levels leave fuels like trees, brush, and tinder dry late autumn and early winter. This increases the chance that snow-free Decembers will leave grasses and roofs exposed to wind-driven sparks and even embers that could ignite them.
The season that brought snow to the West, and cool, rainy weather to many other parts of America used to be called the start of the season. But it is more like late summer. Even if global warming didn’t ignite the Marshall Fire, “there really is a seasonality change that is the main climate factor,” said UCLA climate researcher Daniel SwainShe studies extremes like floods and fires. “Usually by this time of year, there is just more moisture on the ground.”
Over the past 20 years, the region has experienced alarmingly rapid desertification that has reduced snowpacks and dried up river flows. It has also seen groundwater levels drop. Denver, located just south of Marshall Fire, saw one of the longest periods of snowless in its history just before the blaze. The West was also hit hard by an extreme autumn heat wave.
Winter fires are not uncommon in Colorado or grassland like the Marshall Fire, Swain noted.
“That is not quite as surprising as what happened next,” he said. “It started there, burned a few hundred acres within 10-15 minutes, then it came across shopping malls … a significant extent of tract homes, a fair bit of vegetation in people’s yards and city parks. This is not a wild place, not a remote place.”
“That’s why we get these eerie images,” he said, alluding to social media posts of people fleeing from shopping mall pizza parlors and medical workers watching the fire from a hospital window as near-hurricane force wind gusts pushed fire and smoke plumes east into the towns of Superior, with a population of 13,077, and Louisville, with 20,860 residents.
The images of fires around shopping malls are jarring, Swain said, “And yet as bewildering as it is, we’ve seen it in any number of large, wind-driven fires in recent years.”
Swain stated that many recent California fires are similar to the Marshall Fire. He cited the 2017 Tubbs Fire, which burned more than 5,000 structures, in Santa Rosa, and the 2018 Camp Fire, which killed more 80 people. Also in 2018, Swain cited the Carr Fire, which crossed the Sacramento River in Northern California, to spread into Redding. Redding is home to 90,000.
Swain stated that December’s temperatures were not unusual for Boulder, with highs of 40 degrees. But that contrasted sharply with a “multi-month period of almost continuously balmy and record-warm temperatures leading up to this event, with many days making into the 60s and 70s during October and November and overnight lows rarely getting below freezing,” he said. “It was those antecedent record warm and dry conditions that were key in setting the stage.”
And the winds that drove the fire were He had never experienced anything like it before. “The strongest I have ever experienced anywhere in the world while outdoors,” said Swain, who had to wear protective glasses to protect his eyes from airborne pebbles and roof shingles, with gusts “rushing downward over the Front Range foothills, creating very erratic windflow and occasional tornado-strength vortices. At one point, I witnessed one of these clear-air vortices cross the road and uproot a tree.”
With the increasing confluence of extreme fire weather conditions like high winds and extended droughts and heat waves, “there are a lot of places that are at similar risk, including many of the suburban areas around the Front Range,” Swain said. “But it’s really hard to prepare. There aren’t any simple interventions.”
Preparing for Wildfires In Suburbia
Veblen, an expert on the geography of fire, stated that one part of the solution lies in revising building codes in order to ensure that landscaping materials and construction are non-flammable. These measures are becoming more common in areas that are well-acquainted with fire hazards. The Marshall Fire may also have an impact on how future boundaries will be drawn.
Veblen stated that fires can spread between jurisdictions. However, state rules would be most beneficial, but they are unlikely to occur in Colorado, a home-rule state where most land use decisions will be made by local governments. So that leaves it up to county commissioners, “who need to feel they have the political support of the people so they can resist the influence of the building and real estate interests, which nearly always oppose any mandatory measures that make building more costly,” he said.
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Insurance industry could also encourage a significant change in building practices. For example, people who build with flame-resistant brick will pay less for fire insurance than those who build with flammable material.
Apart from the built environment, he said the Marshall Fire will also trigger some “serious rethinking” of wildfire mitigation and the management of open space and parklands, which are among the key amenities that make the nearby homes desirable in the first place.
“We know that up until 1950 it was mostly ranchland,” he said, with grazing cattle keeping grasses short and less prone to fire. Residential development started after World War II and accelerated in the 1970s.
“The most important thing we’ve done is change the fuels by putting structures all over the foothill ecotone,” Veblen said. Early reports about the Marshall Fire suggest that it may have slowed when it reached an area where cattle still eat grass. He suggested that managed grazing could also be an option to reduce the risk of fire. By adding moist firebuffers to the landscape, we can also help to restore streams and wetlands to the point where they support live vegetation.
The Marshall Fire and similar blazes burning in unusual landscapes and seasons could also challenge assumptions about how to reduce the wildfire hazard in areas far from the towns that burned—the fire-prone zone where forests spill off the lower slopes of the Rockies onto the plains. The traditional thinking was to reduce woody fires.
“But if you thin out ponderosa pine, it increases resources for grass to grow,” Veblen said. “So we said, ‘Sure, let’s have some grass fires, that will be beneficial.’ But no one was thinking about this. Wow, this fire event is changing my perspective on where it is or is not safe from fire.”
Source: Inside Climate News