Over the past four years, the Upper Canyon of the Middle Fork Salmon River has undergone a remarkable transformation, driven by wildfires and the powerful erosional events that followed. These blowouts serve as striking reminders of nature’s force—but also offer a rare opportunity to witness, firsthand, how quickly a landscape and river can evolve. Below is a brief timeline that helps illustrate the scale and sequence of these events, and the natural forces behind them.
The Boundary Fire in August 2021
In August 2021, a lightning strike ignited the Boundary Creek Fire less than two miles west of the Boundary Creek boat ramp. The Upper Canyon’s topography, a mix of steep slopes and densely forested terrain, proved highly susceptible to active wildfire behavior. The fire spread along the river corridor, climbing tributaries and consuming vast swaths of forest. This event was a defining moment for the area, leaving the landscape primed for the erosional events that would soon follow.
Setting the Stage
To fully understand the changes in the Upper Canyon, it’s important to examine the relationship between wildfire and erosion, two forces that have long shaped the Middle Fork’s landscape.
Why do blowouts happen? One major factor is how fire alters soil absorption. When vegetation burns, it removes the natural cover that protects the soil, reducing rainfall interception, infiltration rates, and surface roughness. This increases the likelihood of surface runoff, erosion, and large sedimentation events that can occur for years after a fire.
Wildfires also weaken root systems, anchors that hold soil in place, and can create water-repellent layers in the soil. Fine grained ash clogs pores on bare soil surfaces, further reducing infiltration. Rapid surface runoff over smooth, erodible slopes leads to sheetwash and rilling, carrying large volumes of ash and sediment into the river system.
2022 and 2023 Upper Canyon Blowouts
The blowouts of 2022 and 2023 stand out for their sheer scale and impact. On August 12th, 2022, almost a year from the Boundary Creek fire, a large rain event poured on the Upper Canyon of the Middle Fork. Numerous tributaries blew out. The following year, on August 3rd, 2023, another series of blowouts occurred after a torrential downpour.
A Landscape Transformed
Matt Leidecker, author of The Middle Fork of the Salmon – A Comprehensive Guide, has done a terrific job capturing the changes that have occurred at Sulphur, Ramshorn, Hell’s Half, and Velvet Falls rapids. The photos featured here were taken by Matt Leidecker and Idaho River Journeys and offer a striking view of a landscape in flux.
Sulphur Slide
Ramshorn Rapid
Hell’s Half Mile
Velvet Falls 2022 Blowout
Velvet Falls 2023 Blowout
Navigating the Challenges
After the blowouts, the next big question was: could we still navigate the rapids? Over the following seasons, Middle Fork crews scouted, discussed, and ran the newly formed rapids. While the technical boating presented fresh challenges, it also proved to be incredibly fun—and exciting—for both guests and guides. The experience reinforced a core truth of river running: you never run the same river twice.
At first, the transformation was startling. Familiar landmarks had changed, rapids were reshaped, and the river felt unfamiliar. But that initial shock quickly gave way to a sense of adventure. For many, it felt like discovering the Middle Fork all over again. It’s a wild river, after all—and we’re fortunate to witness its history unfold right before our eyes.
