The National Weather Service in Boulder is reviewing how it warns the public about high fire danger after embers carried by 100 mph wind gusts exploded into the most destructive inferno in Colorado history.
The office said it plans to review the standards it uses to declare red flag warnings, and whether to reduce the threshold to put them in place in advance of dangerous conditions. In many Colorado counties, including Boulder County, a red flag warning automatically triggers a county burn ban applying to private and public lands.
No red flag warning was in effect when the Marshall fire blew up Dec. 30, although fires were banned because of a separate high wind warning, authorities said.
Still, the lack of a red flag warning during such extreme conditions underscores a national debate over the potential for muddled messaging when it comes to warning residents living in disaster-prone areas.
One challenge meteorologists must address is how to effectively communicate with both the public and public emergency management.
“Messaging is a really big issue if we are going to both serve these two populations of fire managers and the general public, you know, how do we develop messaging that’s really effective?” Tamara Wall, a researcher at the Desert Research Institute, said during the American Meteorological Society’s annual meeting in 2019.
Some experts fear that red flag warnings are losing effectiveness because of the frequency with which they are issued, causing agencies and the public to grow “numb” to the messages, the National Oceanic Atmospheric Administration wrote in a 2020 statement.
There’s also confusion between the weather service’s advisories, including a red flag warning, and a fire weather watch, which alerts land management agencies to the high potential for red flag conditions to develop in the next 12-72 hours.
On the morning of the Marshall fire, stage 1 restrictions banned most burning, including open fires and campfires. But a high wind warning, issued by the weather service, bumped the county’s burn ban up to a level 2 restriction, banning all burning on public and private land with the intent “to dissuade all burning or use of fire for the greater public safety,” Seth McKinney, Boulder County’s fire management officer, said.
While the Boulder County Sheriff’s Office prohibits open burning under both high wind warnings and red flag warnings, the latter could influence resource management among first responders.
“The challenge with this is that sometimes these NWS events come with short notice. Therefore, we know that messaging and enforcement is challenging – but we are able to stop people from doing any kind of burning when they call their burn in to our dispatch center,” McKinney said.
But no red flag was declared because relative humidity levels did not dip below a threshold of 15% for at least three hours, a requirement under the agency’s criteria to issue a red flag warning, Greg Hanson, a National Weather Service meteorologist in Boulder said.
“I think the Marshall fire is good evidence of that – where you can still get extreme fire behavior when we’ve got those very strong winds, 80 mph winds, even when we’re not hitting those low humidity levels,” Hanson said. “So that’s, that’s evidence right there, that it’s something we need to take a look at.”
An investigation into the fire’s cause remains ongoing, centered near Marshall Road and Colorado 93, near a burning shed that marked the first known structure to catch fire.
A potential change in the threshold for red flag warnings will take time and include discussions with the weather service’s office in Grand Junction and Pueblo, as well as the U.S. Forest Service, fire districts, other federal land management agencies and state and local emergency management groups, Hanson said.
Marshall Fire coverage
Part of the uncertainty around red flag warnings stems from the fact that they were never really intended to serve the public, meteorologists say.
The term dates back to the 1960s and refers to when forecasters hoisted a red flag to alert land management agencies about the onset of critical weather and fuel moisture conditions that could lead to rapid or dramatic wildfire activity that might threaten firefighter safety, according to the American Meteorological Society. But in the past decade, its purpose has evolved to also become a warning for the general public, alerting them of extreme fire risk.
“So it’s gotten a lot more wider use, which is good, it does raise awareness,” Hanson said. “But we’re finding now that it may be used in ways that it originally wasn’t designed for.”
Hanson said his office plans to talk to its partners to see if criteria for red flag warnings need to change, or if there are better ways to convey risk to the public when conditions don’t reach the warnings’ thresholds.
The dual role of red flag warnings has led to a project among several organizations across the country to look at the effectiveness of the warnings and assess whether changes are needed to the weather service’s criteria for its advisories.
The study, launched in 2018, was designed with the goal to create a new red flag warning system that meets the needs of the National Weather Service, the fire management community and the general public.
In Reno, Nevada, National Weather Service forecasters decided they were issuing red flag warnings too often, prompting them to analyze the conditions on the days with conditions that met the criteria for such warnings, Wall, the fire researcher, said in the presentation. They then created an enhancement to a red flag warning, called a “Particularly Dangerous Situation,” to identify days that qualify in the top 1% most extreme conditions.
The office, which forecasts for northeastern California, issues those warnings about once a year, including before the 2018 Camp fire, the state’s deadliest and most destructive fire. They alerted an energy company of the situation, prompting them to shut off electricity, Wall said.
“I think that really brought home to everybody involved in this, the importance of really developing effective communication and messaging and doing it in a way that was timely and really relevant to communities that have often difficult times evacuating during very emergent fire events with extreme fire behavior,” Wall said.
National Weather Service offices in California have also started to use the new term.
The lack of consistent standards for what constitutes red flag weather is a continuing challenge, Wall said.
“We really need to identify threshold criteria and we need to do it in a way that has a consistent methodology across the United States,” she said.