416. Kenyon (2016) Assessment, restoration, and management of the North Puyallup Trail, Mount Rainier National Park
     The N Puyallup Trail, on Klapatche Ridge in Mount Rainier National Park, was originally the end of the Westside Road. The N Puyallup Trail has developed issues of surface erosion and landsliding since the area east of Klapatche Point was converted to wilderness area in 1988 (Owens, 2006). The wilderness designation limits the park's ability to provide cyclic maintenance using motorized equipment. As a result many features on the trail are damaged by infilling of soils, erosive damage from the lack of surface water management, and landslides (Owens, 2006). These conditions have resulted in damage to the trail surface and the production of harmful sediment inputs into the N Puyallup River, home to the endangered bull trout (ECOS, 2015). A major task for this project was to determine and catalogue features on the site worthy of priority status for restoration or repair. The ultimate goal of the investigation was to recommend repairs that would protect the road surface while also minimizing the production of fine sediment and landslides that reach the N Puyallup River. In doing so, this project helps safeguard both the historic trail and the sensitive river ecosystem downslope from further harm. My results indicate that the most significant concern is unmanaged surface water on the trail. These flows have led to surface erosion to the trail surface and fill slope, deposition of sediments onto the trail surface, and shallow landslides. In many cases issues of drainage occur in combinations at a single point. This can be seen as deposition of alluvial materials coming from multiple channels, excess water incising the trail surface and being pirated down the road grade, and incision leading to a point where the flow path is occasionally directed off the fill slope causing erosion and mass wasting. Debris flows are the most common form of mass wasting on the trail, and most of these have surface water piracy as either triggers or at least contributing to their instability. All debris flows on site are sourced from the fill slope of the trail. Most debris flows on site transport material into pre-existing channel convergences, but some have scoured new paths downslope that are now being occupied by pirated surface water flows. Rockfall occurs across the length of the trail on several headwalls with slopes greater than 45 degrees, and appears to be independent from drainage problems on site. Points posing the greatest threats to the trail include upslope headwalls producing both dry rockfall and shallow slides. Colluvial hollows left by debris flows show headward retreat, narrowing the width of the trail and oversteepening slopes. The steepest sections of ridge have rockfall accumulating near the fill slopes, narrowing the trail further and loading the already at-risk slopes. All points mapped for this investigation were at risk of damaging the trail surface, affecting the water quality of the N Puyallup River via fine sediment inputs, or harming the overall quality of the river habitat via landslides. The combinations of surface erosion and mass wasting types were the deciding factor as to what designs are recommended at each point. The list of repairs includes culvert restoration, waterbar installation, segments of ditch clearing, spillways for drainages, soil bioengineering to add root stability, buttressing of colluvial slopes, and gabion reinforcement. The top priority is the cleaning or replacement of culverts. Culverts in my designs are used to handle areas that need to pass high or constant discharge, and their flow paths are built to drain into stable channel networks. I have recommended that they be replaced by high volume relief drainages to allow them to be maintained without the assistance of machinery. Waterbars should be used to provide erosion-resistant flow paths, allowing us to direct water toward more stable outlet locationsalong the fill slope. These will be installed in multiples, enabling the new drainage to handle various flow levels and be able to withstand at least one slope failure. Using waterbars helps reduce the problems of water piracy and direct surface water away from the crowns and scarps of mass wasting features. Soil bioengineering is a low-cost, easily-installed approach for reinforcement of unstable soils along the site, encouraging a progression toward a naturally stable state (Polster, 2002). I have recommended the use of wattle fences to reinforce the headwalls of colluvial hollows, and live staking on oversteepened fill slopes. I also recommend the use of live staking as buttressing measures intended to reduce effective slope and act as a colluvial storage system. Rockfall should also be unloaded where it is piled near stone walls, near steep slopes, or narrows access to the trail. After repairs are completed efforts should made to establish annual or bi-annual monitoring and maintenance procedures to ensure that the trail progresses toward a stable state, remaining accessible to visitors and environmentally friendly. Maintenance actions will also be partly dependent on the monitoring process, as some features will not need maintenance unless they fail. This will help determine when maintenance is required and where it should be focused. Regular maintenance procedures should be performed every 2 or 3 years because the chosen designs should make most of the structures somewhat self-cleaning and fail-safe. Investigation should be performed for any components of the site that I was not able to. The features that I think will need better investigation are of the condition of each of the stone walls, and the natural channels that contact the trail from upslope. For walls investigation should note the slope of the front face and the integrity of walls to see if their condition is deteriorating. Channels contacting the trail from upslope should be investigated to assess the discharge and flow paths of each, allowing for continued monitoring. These channels exist at some of the most unstable points on the trail and have and are generally the primary source of surface water at those points. Increases in discharge or changes in flow path on the trail could necessitate that changes be made to the local drainage networks and other reinforcements. If all these plans are followed the N Puyallup Trail should remain stable and even become a higher quality experience for park visitors.
544. Zawol and Kenyon (2026) Behind the curtain: Developing methods and toolkits supporting practical assessment of discharge and bedload of the Nisqually River within Mount Rainier National Park
     Impacts from a changing climate continue to drive changes in the hydrology, geomorphology, and inherent variability of the world's rivers. Upland watersheds with strongly coupled fluvial/hillslope dynamics are especially vulnerable to these effects, leaving mountainous watersheds in a precarious position. Classic methods for hydrologic monitoring are almost exclusively developed for rivers with slopes of <0.001 m/m, leaving steep mountain rivers comparatively unstudied, and slow to advance by comparison. This work seeks to continue efforts from the Mount Rainier National Park (MORA) Imminent Threats Program to address research gaps pertaining to the continuous measurement of discharge and sediment transport in mountain rivers with a slope ≥0.02 m/m, furthering our understanding of impacts to morphodynamic processes advancing into downstream communities. Containing widely distributed low-resilience infrastructure, significant increases to precipitation intensities, and glacial recession rates greater than 0.1 m/day, the Nisqually River of MORA exemplifies the nexus of modern land management issues driven by climate stressors of the Pacific Northwest. With this study, we seek to further characterize observable surface processes in the Nisqually watershed within MORA and consider new frameworks enabling reliable monitoring of steep mountain rivers. Here, we continue the efforts to refine the use of seismic analysis focused on pristine mountain rivers by creating tools to package analyses, and testing combinations of field practices for calibrating model frameworks. We combine visualization and data selection tools to aid large data management of our repository (>10TB), targeting analysis for time periods of interest. We also attempt to use experimental schema of active-source calibration testing for stations within a remote monitoring network to determine Green's function parameters, moving from relative monitoring toward quantifying discharge and bedload. If successful, MORA will finally begin collecting a record of river discharge after 127 years of management.
543. Wood and Peters (2026) Influence of modeling assumptions on pedestrian evacuation success for non-eruptive lahar hazards at Mount Rainier, Washington
     Previous efforts to characterize lahar threats posed to communities downstream of volcanoes have focused primarily on delineating hazard zones that lack information on lahar-arrival times and exposure estimates that implicitly treat threats to be the same regardless of distance from the volcano. Estimated lahar-arrival times, travel times for individuals to leave hazard zones, and possible evacuation delays related to event identification, warning dissemination, and evacuee behavior are important, but often overlooked, aspects of understanding the societal threats posed by lahars. These temporal considerations are important for unexpected lahars that could occur due to slope failure in the absence of precursory volcanic unrest or eruption. This case study examines the role of time in lahar evacuations by quantifying population exposure and evacuation potential for non-eruptive lahar hazards associated with Mount Rainier, Washington. Lahars could directly affect tens of thousands of residents and employees, thousands of students at primary and secondary schools, and hundreds of individuals at long-term residential care facilities. Geospatial path-distance modeling quantified evacuation potential for 736 scenarios that represent combinations of lahar sources, evacuation destinations, pedestrian travel speeds, and a range of departure-delay assumptions. Depending on location, some communities may have substantial loss of life in tens of minutes after lahar initiation, whereas other communities may be managing large-scale evacuations over several hours. Estimates of evacuation success based on a range of scenarios provide individuals in hazard zones and risk-reduction agencies with insights on how their actions may increase or decrease the number of people that survive future lahars.
542. Raup et al. (2025) Tracking extinct glaciers in GLIMS
     Global Land Ice Measurements from Space (GLIMS), an initiative to build and distribute a database of global glacier data, has recently begun to track glaciers that have recently disappeared. GLIMS provides a definition of “extinct” glaciers for our community, and the final determination of extinction is left to local experts. There are currently 181 glaciers in the GLIMS Glacier Database that are marked as “extinct”, though we recognize that there have been many more reported in the literature. GLIMS welcomes more submissions to make the list more complete.
541. Carlson et al. (2026) Disappearing glaciers of the Oregon Cascades, USA
     The Oregon Cascades had 35 named glaciers on seven volcanoes in the 1980s, with 34 of those glaciers remaining by 2000. Here, we document the glaciers that fall into the Global Glacier Casualty List categories based on five years of field observations of these 34 glaciers. Five glaciers have disappeared, four have almost disappeared and eight are critically endangered. Thus, half of the Oregon Cascades named glaciers have disappeared, almost disappeared, or reached critically endangered status in the 21st century. Between 1980 and 2024, the May–October ablation season of the Oregon Cascades region warmed at ∼0.3°C per decade, with a 2020–24 mean temperature ∼1.7°C warmer than the 1975–84 mean. In contrast, there was no significant trend in November–April accumulation season precipitation. Given the significant rise in melt-season temperature, we attribute ongoing glacier disappearance in the Oregon Cascades to the warming climate.
540. Ghent et al. (2026) When every second counts: Parental decision-making in Mt Rainier’s lahar inundation zone
     Mount Rainier, a heavily glaciated stratovolcano in Washington State [USA], has a documented history of producing major lahars. The potential for future high-magnitude flows threatens approximately 90,000 downstream residents and has prompted one of the nation’s most extensive volcanic monitoring systems, including a specialized lahar detection network. Because portions of Rainier’s west flank are composed of hydrothermally altered, unstable rock, the region is especially vulnerable to “no-notice” lahars triggered by sudden, non-eruptive slope failure. In response, schools in at-risk zones have conducted lahar evacuation drills – now a legal requirement – for over two decades, demonstrating that on-foot evacuation is the most effective strategy for student and staff safety. Despite these efforts, many parents report an intention to retrieve their children from school during an emergency lahar evacuation, contradicting official guidance. Such actions could obstruct evacuation routes, delay emergency response, and increase personal risk, especially in areas where modeled lahar arrival times are under one hour. Parent decision-making thus presents a critical, yet understudied, variable in evacuation planning and is considered integral to the success of city-wide evacuations. Here we present the ongoing work from focus groups held with local parents to explore motivations behind their intentions. Topics of discussion within the focus groups include parents’ general understanding of lahar hazards, their intended actions, their confidence in school evacuation plans, and underlying factors in their decision-making. These insights can support more effective communication and preparedness strategies by emergency managers and school officials, while also contributing to broader discussions about protective action decision-making in rapid-onset hazards beyond volcanic settings.

View More Publications...

The U.S. Geological Survey Cascades Volcano Observatory and the University of Washington Pacific Northwest Seismic Network continue to monitor Washington and Oregon volcanoes closely and will issue additional notifications as warranted.

Website Resources

For images, graphics, and general information on Cascade Range volcanoes: https://www.usgs.gov/observatories/cvo
For seismic information on Oregon and Washington volcanoes: http://www.pnsn.org/volcanoes
For information on USGS volcano alert levels and notifications: https://www.usgs.gov/programs/VHP/volcano-notifications-deliver-situational-information

Jon Major, Scientist-in-Charge, Cascades Volcano Observatory, jjmajor@usgs.gov

General inquiries: vhpweb@usgs.gov