Tunnel Fire in Northern Arizona grows to 20,000+ acres

Strong winds have spread the fire for 12 miles to the northeast

Updated 10:46 a.m. MDT April 21, 2022

From the staff at Sunset Crater Volcano National Monument, which was overrun by the Tunnel Fire.

“April 20

“All Sunset Crater Volcano and Wupatki staff are accounted for and safe. We were also able to successfully evacuate all culturally important items from the visitor center. For those who worried, the Kabotie painting, corn rock, Qa’na Katsina doll, and other items are safe.

“As of 4:45 this morning, the visitor center remains unharmed, as well. However, active fires continue to burn nearby. Sadly, Sunset Crater Volcano National Monument has burned in its entirety. The park is closed, and we do not have any estimated timeline for reopening.”

Sunset Crater Volcano National Monument
File photo of Sunset Crater Volcano National Monument, May 20, 2017.

In the map below, the Monument is inside the yellow border.

7:57 a.m. MDT April 21, 2022

3-D Map Tunnel Fire at 12:30 a.m. MDT April 21, 2022
Map of the Tunnel Fire. Looking southwest at 12:30 a.m. MDT April 21, 2022.

The Tunnel Fire five miles north of the Flagstaff suburbs grew by about 3,000 acres Wednesday to bring the size up to more than 20,500 acres.

To see all articles on Wildfire Today about the Tunnel Fire, including the most recent, click here.

The fire started during the afternoon of April 17 west of Highway 89. Pushed by strong winds it spread rapidly to the northeast, crossed the highway, burned through Sunset Crater Volcano National Monument, crossed major electrical transmission lines, and early Thursday morning was about 10 miles east of Highway 89 approximately two miles from burning out of the Coconino National Forest.

Map Tunnel Fire 12:30 a.m. MDT April 21, 2022
Map of the Tunnel Fire at 12:30 a.m. MDT April 21, 2022. The brown shaded areas represent intense heat at the time the fire was mapped.

On Wednesday crews worked to keep the fire out of the Timberline Estates and Wupatki Trail subdivisions. They encountered natural gas leaking from foundations of burned structures, which slowed suppression activities. On Tuesday fire officials said 24 structures had burned. The number was not broken down by residences or outbuildings.

Strong winds on Wednesday again limited the ability of aircraft to safely and effectively support firefighters on the ground. Conditions are expected to become windier Thursday and Friday. A Red Flag Warning is in effect Thursday until 8 p.m. MST due to predicted gusts of 40 to 50 mph and 10 to 15 percent relative humidity.

Tunnel Fire, April 19, 2022
Tunnel Fire, April 19, 2022, as seen from O’Leary Lookout in Northern Arizona. USFS photo.

A National Type 1 Incident Management Team was ordered Tuesday. The 76 personnel with the team will begin arriving Thursday, with plans to assume command from the Type 3 IMT Friday morning.

Firefighting resources on scene include three dozers, 24 fire engines, and one Type 3 helicopter, for a total of 260 personnel.

U.S. Highway 89 is still closed from milepost 425 (Campbell Road) to milepost 445 and will likely remain closed for the next several days due to firefighting operations.

Information about evacuations, structures that have burned, and when people might be able to return is handled by Coconino County, which is posting updates online.

Satellite photo fires in Arizona, 6:31 p.m. MDT April 20, 2022
Satellite photo showing smoke from fires in Arizona, 6:31 p.m. MDT April 20, 2022.

Tunnel Fire spreads across Hwy. 89 north of Flagstaff, AZ

A Type 1 Incident Management Team has been ordered

Updated 4:09 p.m. MDT April 20, 2022

The National Weather Service has issued a Red Flag Warning for northern Arizona from 11 a.m. until 8 p.m. MST, for 15 to 25 mph winds gusting to 35 and 11 percent relative humidity.

To see all articles about the Tunnel Fire on Wildfire Today, including the most recent, click here.

Updated 11:20 a.m. MDT April 20, 2022

map Tunnel Fire 4 a.m. April 20, 2022
Map of the Tunnel Fire 4 a.m. April 20, 2022. The green line designates the “go”, evacuate now area. The yellow line is the “set”, be prepared to evacuate area.

The Tunnel Fire north of Flagstaff was mapped at approximately 16,625 acres at 4 a.m. Wednesday. The map above shows the go-now evacuation areas in green which affect about 750 homes.

Tuesday afternoon and night the fire burned through the Sunset Crater Volcano National Monument and kept going toward the northeast for another three to four miles. At 4 a.m. Wednesday it was about three miles from burning out of the Coconino National Forest.

The Arizona Department of Transportation reports that US Highway 89 is closed in both directions. There has been no update on the number of structures destroyed since Tuesday when it was announced that 24 had burned. The number was not broken down by residences or outbuildings.

Tunnel Fire, April 19, 2022
Tunnel Fire, April 19, 2022.

The winds on Wednesday are predicted to be less extreme than on Tuesday. The National Weather Service forecast calls for 20 mph winds gusting out of the southwest at 25 mph, with 17 percent relative humidity under clear skies. The wind speeds will increase on Thursday, 23 mph gusting to 35, still out of the southwest and 18 percent relative humidity. Then on Friday the speeds increase to 29 mph gusting to 45 mph from the southwest, but with higher humidity — 30 percent —  and a chance for 0.01 inch of rain Friday afternoon.

The Incident Management Team was apparently too busy Tuesday evening to submit the routine Incident Status Summary report, therefore limiting the amount of specific information available. A Type 1 IMT, Northwest Team 3 with Incident Commander Johnson, has been ordered.

10:13 p.m. MDT April 19, 2022

Map Tunnel Fire, 6:21 p.m. MDT April 19, 2022
Map of the Tunnel Fire, 6:21 p.m. MDT April 19, 2022.

The Tunnel Fire four miles north of the Flagstaff suburbs was very active Tuesday afternoon, spreading across Highway 89 into Sunset Crater Volcano National Monument. Authorities with the Coconino National Forest estimated that by late in the afternoon on Tuesday it had grown to about 6,000 acres.

It was reported at 4:22 p.m. on Sunday April 17 (however some sources say it was on April 18). The cause is under investigation. Coconino County has the official evacuation information.

Tunnel Fire, April 19,2022
Tunnel Fire looking north from Lunar Dr. just south of Silver Saddle, April 19, 2022. Photo by Deborah Lee Soltesz.

Strong southwest winds that pushed the fire to the northeast are predicted to continue through Tuesday night at 30 mph gusting at 40 to 54 mph while the relative humidity remains below 30 percent. On Wednesday the winds will still be out of the southwest, but will decrease to 10 to 20 mph with gusts up to 30 mph while the relative humidity drops to 17 percent. With that forecast the fire will likely remain very active Tuesday night moving northeast.

The Forest Service said Tuesday night that 24 structures had burned.

Firefighting resources assigned include five handcrews, 15 engines, and three dozers. Air tankers were ordered Tuesday afternoon but had to be grounded due to very strong winds.

A Type 1 Incident Management Team has been ordered.

Data shows building codes can reduce vulnerability of homes in wildfires

Slave lake burned homes
Burned homes in Slave Lake. May 16, 2011. Alberta, Canada. CTV.

Researchers have found that building codes based on lessons learned during the deadly 1991 Tunnel Fire in the Oakland Hills of California can reduce the vulnerability of homes to wildfires.

In a paper titled Mandatory vs. voluntary adaptation to natural disasters: the case of U.S. Wildfires, authors Patrick W. Baylis and Judson Boomhower describe how they scoured property and wildfire records to identify which homes were constructed under building codes requiring enhanced resistance to wildfires.

Chapter 7A of the California Building Code which went into effect in 2008 requires certain fire resistance measures, including exterior construction materials used for roof coverings, vents, exterior walls, and decks. It applies to new construction of residential and commercial buildings in designated fire hazard severity zones.

The researchers discovered that a 2008 or newer home is about 16 percentage points (40%) less likely to be destroyed than a 1990 home experiencing an identical wildfire exposure. There is strong evidence, they concluded, that these effects are due to state and local building code changes – first after the deadly 1991 Oakland Firestorm, and again with the strengthening of  wildfire codes in 2008. The observed vintage effects are highly nonlinear, appearing immediately for homes built after building code changes. There are no similar effects in areas of California not subject to these codes or in other states that lack wildfire codes.

Their findings are similar to those in a paper published October 4, 2021 in which researchers analyzed the structures that were destroyed and those that survived the Camp Fire that ran through the city of Paradise, California in 2018. They considered at least four primary characteristics of structures:

  • Were they built before or after the adoption in 2008 of Chapter 7A of the California Building Code.
  • Distance to nearest destroyed structure.
  • Number of structures destroyed within 100 meters.
  • Pre-fire overstory tree canopy within 100 meters

They found that the last three criteria were the strongest predictors of survival. Homes more than 18 meters (59 feet) from a destroyed structure and with less than 53 percent pre-fire overstory canopy within 30 to 100 meters (98 to 328 feet) survived at a substantially higher rate than homes in closer proximity to a destroyed structure or in areas with higher pre-fire overstory canopy. Most fire damage to surviving homes appeared to result from radiant heat from nearby burning structures or flame impingement from the ignition of near-home combustible materials. The researchers concluded that building and vegetation modifications are possible that would substantially improve outcomes. Among those include improvements to windows and siding in closest proximity to neighboring structures, treatment of wildland fuels, and eliminating near-home combustibles, especially within 1.5 meters of the structure.

(The video below was shot December 31, 2021, the day after the Marshall Fire destroyed more than 1,000 homes in Boulder County, Colorado. Notice that most of the surviving homes seen in the video had fewer homes in close proximity.)

The authors noted that while Chapter 7a includes requirements not found in many building codes, a few other codes are more complete incorporating multiple construction classes based on anticipated radiant heat, flame, and ember exposure levels. For example Chapter 7A does not consider the interaction between components such as siding, window, and the under-eave area on an exterior wall.

California is embarking on a pilot project in which owners of vulnerable homes in lower income neighborhoods will be given grants up to $40,000 to retrofit the structures, making them more resistant to wildfires.

Home Ignition Zone

This data helps to illustrate that the condition and characteristics of the Home Ignition Zone should be an extremely high priority in preventing structures from burning as a wildfire approaches.

There is an opportunity for much needed improvement in both current building codes and how we live in wildfire prone WUI areas.

Thanks and a tip of the hat go out to Gerald.

Are planned communities safe from wildfires?

And, can we learn to adapt to fire?

Today I was reading an article about how the communities in Northern California are dealing with the risk from wildfire. One item that got my attention was where a “forestry and wildfire specialist” was quoted describing the Fountaingrove area of Santa Rosa which was devastated by the Tubbs Fire in October of last year.

…a housing development in a rural area that had been built following the highest fire safety standards. Vegetation had been cleared as required, and the homes were built of fire-resistant materials.

The article correctly stated that the development had been “reduced to ashes by the Tubbs Fire”.

“How could that have happened?”, I thought. Fire resistant building standards and cleared vegetation? Firefighters know that if those two characteristics can be checked off, a structure has a much better chance of survival. So how did the community get wiped out?

The Fountaingrove community is 4 miles north of the intersection of Highways 101 and 12 in Santa Rosa. The Tubbs Fire, the deadliest of the fires in 2017, burned into the north section of Santa Rosa, including the Fountaingrove area. It killed 22 people, destroyed 5,643 structures, and burned 36,807 acres.

map Pocket, Tubbs, Nuns, and Atlas
Map showing the perimeters of the Pocket, Tubbs, Nuns, and Atlas Fires. CAL FIRE October 15, 2017.

I would not call Fountaingrove a “rural area”. The thousands of homes there are very tightly packed, as you can see in the satellite photo below taken about five months before the Tubbs Fire.

Satellite photo Fountaingrove
Satellite photo of an area in Fountaingrove May 17, 2017, before the Tubbs Fire. Google Earth.

The next three photos are all of the same area, showing structures on Fir Ridge Road before and after the Tubbs Fire of October, 2017.

Fir Ridge Road
Fir Ridge Road area of Fountaingrove before the Tubbs Fire. Google Maps.
Satellite photo Fir Ridge Road
Satellite photo of the Fir Ridge Road area in Fountaingrove, June 16, 2017. Google Earth.
Satellite photo Fir Ridge Road
Satellite photo of the Fir Ridge Road area in Fountaingrove, October 17, 2017. Google Earth.

The photo below was taken before the fire, a few blocks south of the ones above. This home and all others around it burned.

South Ridge Road Fountaingrove
A home on South Ridge Road in Fountaingrove before the Tubbs Fire. Google Maps.

The Fountaingrove area burned in the 1964 Hanley fire. During the 53-year period until the next fire, the 2017 Tubbs Fire, the houses grew back along with a great deal of vegetation. Most of the homes have shrubs in the yards and multiple large trees, often between the houses that are very close together. Some of the structures are partially obscured from aerial photos by limbs hanging over the roofs.

It is difficult to tell if the homes in these photos were constructed of fire resistant materials. But it is clear that other Firewise principles were not being followed.

firewise wildfire risk home tree spacing
Firewise vegetation clearance recommendations. NFPA.

In a fireprone environment there should be no flammable material within 5 feet of a structure, and in the Home Ignition Zones 5 to 100 feet away, trees need to be 6 to 18 feet apart depending on the distance from the building. If on a slope, these distances have to be increased substantially.

An excellent video that elaborates on these principles has been produced by the NFPA. It points out that the areas in between the trees do not have to be nuked. But to be fire resistant they need to consist of green grass or fire resistant small plants, and should be raked or mowed close to the ground.

If a structure meets these Firewise guidelines, it stands a much better chance of surviving a wildfire. However, if the weather conditions are extreme, such as 60 mph winds and single digit humidity which can lead to spot fires igniting a mile ahead of the main fire, it can be difficult to save a structure.

Most homes are ignited not by the main flaming front of a fire, but from burning embers that land out ahead and start new fires. Likely receptors for these embers are leaves in a gutter, mulch, wooden decks, lawn furniture, attic vents, and accumulations of dead grass, pine needles, leaves, and other flammable material.

When a community is initially planned, the engineers may have done some things right, such as the design of the streets, and water systems. But if everything else is left up to the knowledge and discretion of developer and homeowner, very important principles might be ignored.

Fountaingrove did not meet all of the Firewise guidelines, but the streets were wide, making it easier for large fire trucks to access the structures. The very close spacing of the homes means that if one burns, the radiant heat alone can ignite its neighbor.

Other things to consider in mitigating the wildfire threat include multiple evacuation routes — if one becomes compromised by the fire, another could remain open. Large open spaces without flammable vegetation can serve as safety zones for residents who can’t escape. Backup electrical power sources that can keep pumps running so that community water tanks remain full can ensure firefighters have water at hydrants.

With the warming climate leading to extreme fires and fire seasons that are nearly year round, it is inevitable that deadly fires will strike many wildland-urban interface communities. Under the conditions we have seen in recent years, casually ignoring the threat will lead to more fatalities and property damage. It is not IF a fire will hit a fire prone area, but WHEN. The best solution is to learn to live with and adapt to fire, not ignore it.

Many factors can lead to an area being vulnerable to wildfire, including fire suppression leading to a buildup of vegetation, density of homes like at Fountaingrove, failure of homeowners to use Firewise principles, lack of community standards, insurance companies not understanding the issue, the federal government reducing expenditures for vegetation management and prescribed burning, lawsuits that halt vegetation management projects, and cutting the numbers of firefighters, air tankers, and Type 1 helicopters. When politicians take hold of just one of these issues while ignoring the rest, it can make it impossible to have a rational conversation about adapting to fire.

Discussions need to be thorough and nuanced, not politicized and influenced by industry that profits from using just a single, ill-conceived concept. And zeroing in on one vague term like “raking” and “poor forest management” simply confuse the general public when the complete picture is not illuminated.

Sierra Club argues against FEMA’s plan for the eucalyptus trees in Oakland’s East Bay Hills

The Sierra Club and the Sustainability, Parks, Recycling and Wildlife Legal Defense Fund (SPRAWLDEF) filed suit on May 26 over plans by the Federal Emergency Management Agency (FEMA) to fund a vegetation-management program in the East Bay hills that would increase fire hazards, threaten endangered species and native wildlife, and increase the financial burden on taxpayers.

“The best way forward is to promote native vegetation that is less flammable and encourages healthy ecosystems and greater biodiversity,” said Sierra Club San Francisco Bay Chapter director Michelle Myers. “That’s a win-win for the environment and for homeowners who want to feel secure that they won’t lose their homes in another Great Fire like the one we lived through in 1991. Unfortunately, FEMA’s approach isn’t in line with the priorities of fire safety and habitat restoration.”

FEMA has over $5.5 million in grant money to disburse for vegetation management in the East Bay Hills from Richmond to San Leandro. These areas contain thousands of acres of highly flammable eucalyptus and non-native pines, which choke out more fire-resistant natives like oaks, bays, and laurel. Flying in the face of the best science and land-management practice, the Sierra Club said, FEMA has signaled its intention to fund a plan to thin flammable non-natives, rather than remove them entirely. The Sierra Club / SPRAWLDEF suit contents that this is the wrong approach.

The Sierra Club and other environmental groups including the Claremont Conservancy, the Golden Gate Audubon Society, and the California Native Plant Society have all advocated for removing all of the flammable eucalyptus and pine trees over time so that less-flammable native habitat can reclaim those areas. In contrast to clearcutting, this approach calls for removing eucalyptus in phases, so that native trees — which cannot grow to full size underneath the eucalyptus canopy — are able to thrive. Mere thinning of eucalyptus and pine plantations in fact denudes hillsides to an even greater extent, as it requires the clearing of native plants in the understory.

Related articles on Wildfire Today:

Eucalyptus and fire
Wildfire briefing, March 11, 2015
A view of the potential in the Oakland Hills through the eyes of an Australian
20 years later, potential for another Oakland Hills fire?
Have some plants evolved to promote fire?
Wildfire news, February 1, 2009

Thanks and a tip of the hat go out to Barbara.

A view of the potential in the Oakland Hills through the eyes of an Australian


1991 Tunnel Fire
1991 Tunnel Fire. Screen shot from the Oakland Wildfire Prevention Assessment District video below.

The Oakland Hills, which was devastated by the Tunnel Fire in 1991, has some things in common with Australia. The most obvious is the eucalyptus trees, a species imported from down under. The volatile highly combustible oil in the leaves causes fires to burn rapidly under them and through the tree crowns. The eucalyptus contributed to the spread of the Tunnel fire, which killed 25 people, injured 106 residents, and burned 3,354 homes.

Christine Erikson has written about fires in Australia and authored a book titled Gender and Wildfire: Landscapes of Uncertainty. During a visit to the United States in which she made presentations at conferences, she toured the Oakland Hills. Below is an excerpt from an article she wrote about the experience:

…I felt right at home amongst the swaying eucalyptus trees, which despite much controversy still stand tall in the Oakland Hills. Yet, unlike the ‘Prepare, Stay and Defend or Leave Early’ mantra that is associated with living in eucalyptus dominated (i.e. fire-prone) landscapes in Australia, it was the continuing absence of an official policy on how to better prepare residents for future wildfires in the Oakland Hill that loomed large for me during the fieldtrip. What should residents do if evacuation is not a feasible option in the future? How can residents prepare so a similar disaster is prevented? These questions linger like ghosts at every twist and turn of the narrow, winding mountain roads where smoke, embers and flames resulted in accidents and panic that fatally trapped residents in 1991.

This ghostly presence clearly has not escaped the attention of the local Oakland Fire Department. In addition to official projects, the Department is now “unofficially” advising residents on what they can do to increase their chances of survival. Preparing properties in the Oakland Hills, however, is easier said than done. The recommended ten-metre clearance around residential homes is unrealistic in most of these neighbourhoods dominated by quarter acre blocks. A representative from the Oakland Hills Wildfire Prevention program pointed out that when these two-dimensional blocks are considered three-dimensionally, thus taking into consideration the considerable hill slope, these blocks become one-acre properties in need of defence. He furthermore spoke to the frustration of local building-, planning- and fire-codes not supporting each other. The statutory law of developing a given property, for example, sits within a planning code that does not necessarily follow local fire safety recommendations. 

The video below, produced by the Oakland Wildfire Prevention Assessment District, discusses the 1991 Tunnel fire and what the city is doing now to mitigate the vulnerability the area has to the next wildfire.