The Pocket Fire, Monsoon Damage and the Work Ahead
When the Pocket Fire reached 100% containment on July 30, it marked an important milestone after more than a month of firefighting north of Sedona. The fire ultimately burned roughly 27,400 acres of the Coconino National Forest, affecting portions of the Dry Creek, West Fork of Oak Creek, Fry Canyon and Upper Oak Creek watersheds. But containment did not mark the end of the fire’s impacts on the landscape. For the trails, canyons and watersheds of the Red Rock Ranger District, another phase is now underway.
After the fire comes the water.
And this year, the timing has been particularly challenging. The Pocket Fire transitioned almost immediately into a very active monsoon season, bringing repeated heavy rainfall and localized flash flooding across the Sedona area. On portions of the burn scar, those storms are falling on a landscape where vegetation and protective ground cover have been significantly reduced. Elsewhere around Sedona, intense localized storms have demonstrated how much damage can occur even outside the fire footprint. The result is a growing trail recovery challenge that will likely extend beyond this monsoon season and, in some locations, into the coming years.
Why an Inch of Rain Is Different After a Fire
One of the most important concepts to understand about post fire recovery is that an inch of rain falling on a healthy watershed and an inch of rain falling on a recently burned watershed can produce two very different events.
Under normal conditions, not all rainfall immediately becomes runoff. Trees and vegetation intercept some of the precipitation. Grasses, pine needles, leaves and other organic material covering the ground slow water down. Healthy soils absorb and store water, while roots and vegetation help hold those soils in place. In many ways, an intact landscape functions like a giant sponge.
Wildfire can change that relationship very quickly. Where vegetation and ground cover have been removed or significantly reduced, rainfall reaches exposed soil more directly. Fire can also alter soil characteristics and reduce infiltration. Instead of soaking into the ground or being slowed across the landscape, a much larger percentage of rainfall can begin moving downhill as surface runoff. That runoff can also arrive in drainages faster, creating a sharper and substantially higher peak flow.
The post fire hydrologic analysis commissioned by Coconino County for the Pocket Fire gives us a remarkable local example of how dramatic that difference can be.
For the West Fork of Oak Creek watershed, engineers modeled identical storms under conditions before and after the fire.
- For a relatively frequent 2 year, 3 hour storm, representing about 0.81 inches of adjusted rainfall across the watershed, the modeled peak flow before the fire was just 26 cubic feet per second, or CFS.
- Under post fire conditions, the modeled water only peak increased to 127 CFS. When an upper end allowance for ash, sediment and debris was included, that modeled peak reached 159 CFS, more than six times the peak before the fire from the same storm.
- For a larger 10 year, 6 hour storm, the modeled peak before the fire was approximately 1,207 CFS. Under post fire conditions, including the modeled sediment and debris bulking, it increased to approximately 2,411 CFS, essentially double.
Those numbers are specific to the West Fork watershed and should not simply be applied to every drainage within the Pocket Fire. But they clearly demonstrate the larger point: the same amount of rain can produce a dramatically different response after a wildfire.
And there is another part of the equation.
As that faster moving runoff travels downhill, it begins picking up what is available along the way: ash, loose soil, sand, gravel, rocks, burned vegetation and woody debris. This material becomes entrained in the flow, adding volume and, more importantly, adding mass and destructive force.
For preliminary hazard planning, the Pocket Fire analysis applied a 25% bulking factor to account for entrained ash, sediment and debris. The report appropriately notes that actual sediment concentrations will vary from storm to storm. So post fire flooding is not simply more water. It can be a faster moving mixture of water, sediment, rock and woody debris capable of eroding streambanks, changing channels, burying crossings and moving material far downstream.
The photos and videos below show the debris, sediment, ash and water damage in the Dry Creek corridor along the AZ Cypress Trail.
Dry Creek drainage corridor near and on the AZ Cypress trail.
Left: AZ Cypress near Snake TH.
Middle: AZ Cypress crossing Dry Creek near Oak trail.
Right: AZ Cypress TH near the parking area.
We Have Already Seen It Happen
This is not just modeled future risk.
One significant rainfall event occurred very early in the monsoon season after the Pocket Fire. Rain fell across the burn scar on July 16 and 17, and a stream gauge on West Fork of Oak Creek recorded a peak flow of approximately 2,160 CFS at 4:25 a.m. on July 17.
Rain gauges throughout the watershed recorded between roughly 0.67 and 1.57 inches on July 17, with several locations also receiving meaningful rainfall the day before. When engineers modeled the July 17 rainfall by itself, the model substantially underestimated the observed peak. Once they included the rain that had fallen the previous day and prewetted the watershed, the modeled peak rose from about 680 CFS to 2,520 CFS, much closer to the observed event.
The assessment concluded that the antecedent moisture had substantially affected runoff response. It also noted field evidence that the actual flow likely transported ash, sediment and debris. That event provides an early real world lesson in why the coming months matter so much.
A watershed does not reset between storms. Saturated soils, newly deposited sediment, altered channels and additional rainfall can compound one another. Conditions after the next storm may therefore be different from the conditions we assessed after the last one.
The photos and videos below show the debris, sediment, ash and water damage in the Dry Creek corridor along the Axis and Girdner trails crossing the Dry Creek drainage.
One Watershed Can Affect an Entire Trail Network
The Dry Creek watershed illustrates why post fire damage cannot be viewed as a problem affecting only the trails that burned directly. Secret Canyon, HS Canyon, Bear Sign Canyon and surrounding drainages funnel water toward the larger Dry Creek system. As runoff concentrates downstream, it passes through a heavily used recreational trail network that crosses these drainages again and again.
Following significant monsoon runoff this summer, we have seen substantial impacts at crossings throughout that corridor. In addition to Secret Canyon, HS Canyon, Bear Sign and Dry Creek, which remained closed following the fire along with David Miller and West Fork, heavy crossing damage has been observed on trails including Chuckwagon, Mescal, AZ Cypress, Girdner, Axis, Outer Limits and RUP.
TrailForks mapping helps illustrate how interconnected these trails are. Mescal, Chuckwagon and AZ Cypress form part of commonly used Dry Creek riding connections, while Girdner connects farther west into the Axis and Outer Limits network.
A damaged drainage crossing therefore does not function as an isolated problem on a single trail. It can affect connectivity across a much larger system. The Forest Service’s reduced Pocket Fire closure following containment specifically kept Bear Sign, David Miller, Dry Creek, HS Canyon, Secret Canyon and West Fork closed for public safety even as many surrounding trails reopened.
Not every damaged crossing will require the same response.
On open trails, some crossings may become better defined again through normal recreational use. Others will require hand work to restore the established alignment. In locations where floodwater escaped the normal channel, damaged the adjoining trail or destabilized streambanks and approaches, considerably more work may be necessary. Those areas can require drainage work, reconstruction and stabilization to ensure that the repair itself does not simply disappear during the next significant storm. Each of those repairs consumes time, people and resources. One damaged crossing may be relatively straightforward. Dozens of damaged crossings, combined with direct fire impacts, routine maintenance and additional monsoon damage across the district, represent something very different.
The Red Rock Ranger District has already planned for Friends of the Forest to begin work on AZ Cypress and the Girdner/Axis crossings pictured above in September; however, the extent of the damage and full scope of work is still being assessed, as monsoonal storms are typical through late September and into early November.
The videos below show the debris, sediment, ash and water damage in the Dry Creek corridor along the Chuck Wagon trail crossing the Dry Creek drainage.
Direct Fire Impacts Are Also Significant
Flooding is only one part of what we are facing.
A recent reconnaissance flight generously provided by Hale Roofing, one of the Sedona Red Rock Trail Fund’s Trail Keepers, gave us an opportunity to see portions of the Pocket Fire area from above. The direct effects of the fire in some locations are substantial. Sections of Secret Canyon Trail and the surrounding landscape experienced very heavy fire effects, leaving portions of the area almost moonscaped. David Miller Trail, which received significant maintenance from the Forest Service trail crew just last year, also experienced heavy fire impacts. Bear Sign Trail was significantly affected as well.
What happens to these areas next will depend in large part on weather. Without the vegetation and ground cover that previously slowed runoff and protected soils, each additional storm has the potential to move more material, deepen drainages, undermine trail tread and change crossings.
We have not yet been able to fully assess every mile of trail within the burn area on the ground. In many places, the final extent of the damage simply has not happened yet.
And the Challenge Extends Beyond the Pocket Fire
The extraordinary maintenance demands this year are not limited to the burn scar.
A particularly intense and highly localized monsoon storm also struck the Bell Rock Courthouse area, affecting the landscape from roughly Hiline toward Llama and numerous trails and drainages below. We do not yet have a reliable rainfall measurement for that individual storm cell, but the evidence on the ground shows the significance of the runoff.
Normally small drainages carried substantial flows toward Cathedral Wash and ultimately Oak Creek. Along Easy Breezy Trail, the effects are especially visible. Water escaped the normal wash channel in places, moved across the trail corridor, transported substantial debris and eroded sections of trail so extensively that portions of established tread became difficult to identify. In some locations, the wash essentially left its banks and became the trail.
A section of trail that took days or weeks to construct and years of incremental maintenance can be dramatically altered in a matter of minutes. That is the reality of maintaining a large trail system in desert terrain during an unusually active monsoon season.
BAER Is Critical, but Recovery Is Bigger Than BAER
The Forest Service’s Burned Area Emergency Response, or BAER, program is an essential part of the post fire response. BAER is specifically intended to identify imminent and unacceptable post wildfire risks to life and safety, property, and critical natural or cultural resources and to implement appropriate emergency stabilization measures. But BAER is an emergency stabilization program.
Forest Service policy separately recognizes longer term burned area rehabilitation and restoration, which can extend for years and relies on nonemergency funding. That distinction matters. Some Pocket Fire needs may qualify for emergency response. Other trail work will fall into the longer process of rehabilitation, reconstruction and routine maintenance.
The role of the Sedona Red Rock Trail Fund is not to replace the Forest Service or its responsibility as the land manager. These trails are on National Forest System lands managed by the Red Rock Ranger District of the Coconino National Forest for the benefit of the public.
Our role is to support that work.
Community donations and partnerships can provide additional resources that complement federal funding and help the Red Rock Ranger District accomplish more than existing capacity alone may allow during an extraordinary year.
This Is a Moment to Give Back
The Pocket Fire demonstrated what can be accomplished when firefighters, land managers, local governments, businesses, organizations and the community work together.
The next phase will require that same spirit of partnership. The U.S. Forest Service and Red Rock Ranger District remain the land managers and will continue leading the management and recovery of these public lands. BAER and other federal resources will address important parts of the work.
The community can help expand what is possible.
Through the Sedona Red Rock Trail Fund, residents, visitors, businesses and everyone who values Red Rock Country have a direct opportunity to provide additional capacity at a time when the need is greater than normal.
That means helping repair washed out crossings. It means helping stabilize damaged trail before another storm makes the problem larger. It means supporting the Red Rock Ranger District as it balances post fire recovery with an extraordinary monsoon season, normal maintenance and important planned projects. It means protecting recreational access, watershed resources, quality of life and an outdoor experience that contributes enormously to the health and economic vitality of this community. Most importantly, it means helping care for an extraordinary public landscape at a moment when that landscape needs additional support.
An inch of rain falling on a healthy forest and an inch of rain falling on a fresh burn scar can be two very different events. This year, we are seeing that difference firsthand. And as the water continues to reshape portions of the landscape, the work required to recover will continue to grow.
If these trails and public lands have given something to you, this is an important time to give something back.
Together, we can help the Red Rock Ranger District bridge an extraordinary year of fire and flooding, restore damaged trails more quickly, and ensure that as the landscape heals, the trail system connecting all of us to Red Rock Country recovers along with it.