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Wildfires run faster
Remember the wildfire in Bambi? Where Bambi and all other the animals are running for their lives from the wildfire? The fire that was started by an unattended campfire? The scary thing is, this scenario is both realistic — animals try to outrun a wildfire — and unrealistic — it’s unlikely that so many of them make it.
You see, wildfires can run faster.
How fast, exactly, depends on three factors:
- Fuel — What’s burning, how dry it is, how much there is, and how dense it is.
- Weather — How windy it is, how hot the air is, and how humid it is.
- Topography — How hilly the terrain is, how steep it is, and how contours run.
The numbers commonly cited as the typical maximum “forward rate of spread” (FROS) are
- 6.7 mph (10.8 kph) in forests
- 14 mph (22 kph) in grasslands
As in the movie, Bambi may be able to make it out. White-tailed deer can run up to 30 mph (48.2 kph). Presumably, that is on level grasslands, not in a forest.
But humans are unlikely to fare as well. The average completion time for a 10K footrace is 1 hour. That’s an average speed of 6.2 mph. So, if you are on the fast side of the average, you might outrun the fire. IF the fire is burning through a forest, AND you’re running on a typical 10K route, that is, reasonably flat, with good footing and no obstructions.
Your best bet is not to be there in the first place. Humans cause 90% of wildfires. Do your part to keep from starting one. If you are in a fire zone, get out as quickly as you can.
But, if you are a backcountry camper, here are some tips for surviving should you find yourself in a bad situation.
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Prescription Rx for our forests?
Photo from WikiMedia Commons
Prescribed burns are nothing new. Native Americans incorporated controlled burns into their culture not just to reduce wildfire fuel, but also as a vital tool in their agriculture and industry.
“Indigenous people have been practicing controlled, deliberate burns in North America, and around the world, for millennia. For the Yurok, Karuk and Hoopa Tribes of Northern California, human-managed fires across their traditional lands are vital. They promote the growth of traditional food sources, like acorns, and basket-weaving materials, like hazel. The fires even support the life cycles of salmon.”
Unfortunately, Europeans came along with an old-world fear of fire and said, “don’t set things on fire!” That led to a practice of forest management that has left our forests with a natural stockpile of wildfire fuel in the form of dead vegetation, and devastated Native American cultures in the process.
But prescribed burns are once again accepted as a valuable wildfire prevention tool. According to Thom Porter, the chief of California’s CalFire wildfire agency, prescribed burns are “our best and most cost-effective tool… to reduce the amount of fuels in the native vegetation areas and also areas that have invasives.” (SF Gate, May 2021)
Indeed, $50 million of California’s $2 billion wildfire and emergency preparedness proposal is slated to fund prescribed burns (SF Gate, May 2021).
A serendipitous experiment on forest resilience to wildfire
A recent accident, reported in the LA Times, has produced strong evidence that prescribed burns can not only reduce the fuel available for a fire to start, but can even make a forest more resilient to wildfires.
The Goosenest Adaptive Management Area is a patch of heavily logged timberland in the Klamath National Forest. In the past twenty years, scientists have worked on an experiment to see how much they could restore the forest to the way it was a century ago. They created four sets of five 100-acre plots, each with a different forest management plan.
Last August, the Antelope fire swept through and burned all twenty plots to the ground, destroying one experiment but creating another:
“Because we have five replicates of each of these treatments that were all hit by fire burning under oftentimes similar conditions, we can tease out the effect of weather and the effect of fuels, It will be a very compelling example of the interaction of fuels treatments and weather in affecting the outcome.”
The results?
“‘In areas where we didn’t do anything, the untreated controls, the predominant fire behavior was a crown fire which killed every tree and consumed the entire tree crown,’ said Eric Knapp, research ecologist with the U.S. Forest Service.
“However, the plots that had been thinned and then treated with broadcast burning — in which an area of land is set alight to mimic naturally occurring wildfire — emerged relatively unscathed.”
Prescribed burns are key to reducing wildfire risk, but federal agencies are lagging – LA Times
Preparing the patient for the medicine
Despite the general acceptance of the efficacy of prescribed burns, they are still not used very much.
“The federal government… has completed only half of the fuels treatments it had hoped to get done in the state for the year — a statistic that profoundly dismayed wildfire experts. … As of mid-September, the Forest Service had completed or contracted out fewer than 37,000 acres of prescribed fire projects in California since Oct. 1, 2020.
“‘That’s just depressing,’ said Lenya Quinn-Davidson, fire advisor for the University of California Cooperative Extension. ‘That’s so little, given how much land the Forest Service manages in California. It is just a drop in the bucket.’”
Prescribed burns are key to reducing wildfire risk, but federal agencies are lagging – LA Times
The problem is that fires are dangerous, and we cannot simply light a fire and hope for the best. To do a prescribed burn takes planning and some luck.
Prescribed burns require:
- the right timing — after the fire season. But the fire seasons are longer than ever leaving less time to perform prescribed burns.
- the right people — seasoned fire fighters. However, the long fire seasons are leaving our professionals burned out when the time for prescribed burns comes along.
- the right forest.. Many of our forests have accumulated too much dead vegetation, making the risk of a prescribed burn getting out of control too high. We first need to thin these forests.
- The right environment — where smoke is not a problem. All fires produce toxic smoke. Prescribed burns can only be performed where weather conditions will not cause smoke to become a health hazard.
Thom Porter believes that prescribed burns will be an important part of wildfire management in the future, but it will take time to get there,
“There are a lot of areas that are overgrown, a lot of areas where it’s not safe to have fires on the ground under any circumstances and that’s why firefighting will continue to be a very important mechanism in our landscape regardless of whether we’re doing prescribed burning or not.
“… once we have safe areas to burn we will reintroduce fire and that will be the primary tool in the future. And I’m talking decades out. I’m not talking about today, tomorrow… We have to build that over an incremental basis over the next many, many years to get to the right place and the right combination.”
It has taken us a while to learn what the Native Americans knew: That fire can be as much a benefit to the health of our forests as a hazard, if we know how to work with it. As we improve forest management, expect to see more fire crews out there conducting prescribed burns.
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P.S. An example of a prescribed burn
To understand just how much planning and care must be taken to perform a prescribed burn, take a look at the Incident Overview of the 53 acre “Valley RX Burns” in Yosemite Valley on Nov 3, 2021.
“Starting Wednesday, November 3rd, fire crews will be prescribed burning units 11 & 16 in Yosemite Valley. This is a continuation of burns conducted a week ago. … Ignitions will occur over the next few days. There will be trail closures in Yosemite Valley, … the objectives of this prescribed burn are to restore and maintain plant communities shaped by Native Americans, restore fire and a more natural ecosystem structure to communities, maintain meadows and healthy stands of conifers, reduce hazardous fuels, and provide protection to infrastructure. Each prescribed burn unit has defined weather parameters and firing patterns to ensure the objectives for each unit have a high potential for success. Yosemite fire and resources staff will monitor all prescribed burns to evaluate achievement of goals and help guide future prescriptions.
Visitors and employees should be aware that smoke may be present starting Wednesday and could linger to a much lesser degree into next week as large logs are consumed. Fire managers work closely with Park staff and the local air pollution control districts to time the prescribed burns to coincide with favorable weather and smoke dispersion conditions. Smoke impacts are always a consideration in the decision to begin any prescribed burning operation. Burning will only be conducted under favorable dispersal conditions as specified in the smoke permit.”
Embers happen!
Photo by Krystle van der Salm on Unsplash
In 2020, a series of wildfires burned in Napa county CA. My mom lived just 25 miles away. She was worried. She had heard that embers can blow miles downwind from a fire and burn down houses.
Was she right to be worried?
Short answer: No. The Napa fires never came close enough for its embers to threaten her home.
Let’s take a look at when mom should worry.
It’s the embers that do it!
Mom was right that most homes that burn down in a wildfire are set on fire by embers falling on them and lighting the house.
“An ember is a small, glowing piece of superheated wood, coal or other material that remains after (or sometimes precedes) a fire. Embers can glow as hot as the fire from which they arise, and are light enough to be carried by the wind for long distances without being extinguished. They’re the primary reason properties go up in flames whenever a wildfire is nearby.”
Red White and Blue Fire says that 60% of homes burn from embers. That site also has a video that dramatically demonstrates that it is embers and not radiant heat that you should worry about.
So, Mom is right to be concerned about embers, but how far can they travel?
How far can embers travel?
Our short answer: Possibly as much as 5 miles, but probably less than 1 mile.
We base that answer by looking at many sources across the web, including these:
“These burning embers or firebrands can travel from one-quarter to one mile in the wind.”
Knowing about fire behavior can protect your home from wildfire
“Flying embers can destroy homes up to 1 mile from wildland areas.”
“But embers can travel several miles ahead of the actual fire due to wind and intensity of the fire.”
“Flaming brands and embers can travel as far as five miles ahead of the active front of a wildfire.”
The most definitive answer we found is in Embers start spot fires: The real and the imagined stories, citing research published in the International Journal of Wildland Fire:
“In a study of 245 extinguished fires, experiments and simulations, and observing 48 wildfires, ‘The longest spotting distance was observed as 2.4 km.’”
The wide range of distances cited reflect that situational conditions play a large role, and whether the authors are trying to emphasize the most likely or the most extreme possibilities. If conditions are right (or wrong, so to speak), high winds and the right kind of material is burning, embers can travel far!
In conclusion
So, Mom needn’t have worried about embers from the fires in Napa. They never got close enough to threaten her house.
However, she should take some simple steps to protect her house by clearing combustibles around it (including the roof).
And then, when the fires are burning, she should monitor alerts from local authorities, even if she does live 25 miles away – fires can move fast.
Finally, of course, should the fire come closer, she should get out early if she felt at all threatened.
17,325 gardens and a scrapie thingie
Photo from InciWeb, Public domain, via Wikimedia Commons
“What people don’t often realize is that hand crews are kind of the cornerstone … putting in hand lines, that’s essentially the way we stop the fire from growing.”
— Mike Johnson, Assistant Fire Chief, Clark County NV
The basic strategy for fighting a wildfire is to clear a “containment line” around it — a perimeter around the fire that is cleared of anything that can burn to keep the fire from crossing — and let it burn itself out.
Doesn’t sound too bad, does it? Just bring in a bunch of bulldozers and large landclearing equipment, and start clearing.
Not so fast. Wildfires are, well, in the wild. That often means inaccessible areas with steep slopes and no roads. Places where you can’t readily get heavy equipment in.
This is where those hardworking dirt-covered fire crews in heavy clothing and backpacks come in. You know, the ones we see pictures of, swinging wicked-looking firefighting tools. They’re building “hand lines,” sections of the containment line that are carved out by hand and hard work.
This video will show you just how hard it is, what a “scrapie thingie” is, and how coordinated a hand crew is.
To get an idea of what building the hand lines in a large fire means, let’s look at an example.
Guesstimating hand lines in the Caldor fire
Containment map of the Caldor fire 2021-10-13
The 2021 Caldor fire in the Sierra Nevadas burned a total of 221,835 Acres (89,773 hectares). Assuming a rectangular perimeter gives us a minimum containment line of 74 mi (119 km). The map shows where the hand lines are, but it’s really hard to read. So, we’ll guess that they constitute about 10% of the containment line, call it 7 mi (11 km).
The rule of thumb is that a fire line (a section of the containment line) needs to be 1.5 times the height of the surrounding fuel. If we assume that we are in a mostly wooded area with trees and bush to an average height of 30 feet (9 m), our fire lines need to be 45 feet (13.7 m) wide, on average.
7 mi x 45 feet gives us an area of
1,663,200 sq ft (154,516 sq m)
that was cleared by hand crews in the Caldor fire.
To put that in perspective, the median vegetable garden in the United States is 96 sq ft (8.9 sq m). So hand crews cleared the equivalent of
17,325 vegetable gardens!
In 68 days. Working at elevations over 6000 ft (1828 m). Wearing a 45 lb (20.5 kg) backpack. Using Pulaskis, McLeods, and “scrapie thingies”!
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It ain’t over till it’s over
Photo from WikiMedia Commons
Just because the fire is gone, doesn’t mean the crisis is over. There is much to do after a fire has swept through your neighborhood.
Returning home
Here are some key safety steps Calfire urges you to take when returning home after being evacuated:
- First of all, do not return to your home until the evacuation order has been or fire officials tell you it is safe to return.
- Before inspecting your home, first check for the smell of gas.
- Look for smoke or sparks throughout the house and on rooftops.
- Do not drink or use water from the faucet until emergency officials say it is okay; water supply systems can be damaged and become polluted during wildfires.
- Discard any food that has been exposed to heat, smoke, flood waters, or soot.
Here’s Calfire’s complete two-page checklist of what to do when returning home after a wildfire.
Mobilize your community
Dealing with the aftermath of a recent wildfire shouldn’t be undertaken alone. Now is the time to work with neighbors: Who has special needs that perhaps you could help with? Who has resources that the neighborhood can share?
Beware that wildfire can cause instability to the ground around you.
“Wildfires dramatically change the landscape and ground conditions, which can lead to the increased risk of flooding even with light rains. … When these normal and protective functions are compromised or eliminated by a severe wildfire the potential for significant erosion, flooding, and debris flows is magnified.”(Calfire, Post-Wildfire Recovery)
Responding to these dangers and solving problems such as debris removal are best approached together.
It takes a long time to recover
Recovery from wildfire damage may require painful decisions, insurance claims, neighborhood clean up, and even home design and construction permitting. It can take years,
“The [neighbors] that I do speak with are on a journey of decision making about whether to rebuild or not. … one day it’s ‘Yes’, one day it’s ‘No’. … It’s over a year later, and nobody has started to rebuild in my neighborhood.”
(JS, after the 2020 CZU Lightning Complex Fire)
The good news is that there are many resources available to help you through the recovery process. CalFire lists non-government, state, and federal organizations that you can turn to. Also, there may be localized resources available to your community.
Finally, understand that recovery does happen and stability does return even though disaster does cause change,
“My neighborhood will never be the same. … People are gone. My dearest neighbors don’t live here anymore. … people whose children I knew since they were born. And just the character of the neighborhood changes, because some of the characters are gone. … But then, there are some situations … I’ve gotten closer to some of the neighbors that have survived, than I was with them before.”
(JS, after the 2020 CZU Lightning Complex Fire)
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