386. Sheridan et al. (2005) Evaluating Titan2D mass-flow model using the 1963 Little Tahoma Peak avalanches, Mount Rainier, Washington
     The Titan2D geophysical mass-flow model is evaluated by comparing its simulation results and those obtained from another flow model, FLOW3D, with published data on the 1963 Little Tahoma Peak avalanches on Mount Rainier, Washington. The avalanches, totaling approximately 10 x 10⁶ m³ of broken lava blocks and other debris, traveled 6.8 km horizontally and fell 1.8 km vertically (H/L=0.246). Velocities calculated from runup range from 24 to 42 m/s and may have been as high as 130 m/s while the avalanches passed over Emmons Glacier. Titan2D is a code for an incompressible Coulomb continuum; it is a depth-averaged, 'shallow-water', granular-flow model. The conservation equations for mass and momentum are solved with a Coulomb-type friction term at the basal interface. The governing equations are solved on multiple processors using a parallel, adaptive mesh, Godunov scheme. Adaptive gridding dynamically concentrates computing power in regions of special interest; mesh refinement and coarsening key on the perimeter of the moving avalanche. The model flow initiates as a pile defined as an ellipsoid by a height (z) and an elliptical base defined by radii in the x and y planes. Flow parameters are the internal friction angle and bed friction angle. Results from the model are similar in terms of velocity history, lateral spreading, location of runup areas, and final distribution of the Little Tahoma Peak deposit. The avalanches passed over the Emmons Glacier along their upper flow paths, but lower in the valley they traversed stream gravels and glacial outwash deposits. This presents difficulty in assigning an appropriate bed friction angle for the entire deposit. Incorporation of variable bed friction angles into the model using GIS will help to resolve this issue.
548. Vaux et al. (2026) Dissolved black carbon in North Cascades snow, meltwater, and a downstream river
     Quantification of black carbon on snow in the Cascade Range is needed due to increasing wildfire intensity and frequency. Here, the benzenepolycarboxylic acid (BPCA) molecular method was used to measure dissolved black carbon (DBC) in snow, nearby rivers, streams, and supraglacial melt collected in 2022 and 2023 from Mount Baker and Mount Rainier. The average DBC concentration in snow was 9 ± 4 μg-C/L and 10 ± 6 μg-C/L in stream, river, and supraglacial meltwater samples. The DBC method provides black carbon source identification via BPCA characterization. DBC concentrations and BPCA proportions were compared to modeled smoke deposition from the Navy Aerosol Analysis and Prediction System reanalysis model. In both years, total deposition from May through October was approximately 670 mg/m2. However, early season smoke deposition (May through July) was four times higher in 2023 than 2022, indicating seasonal variability in the timing of deposition. Dry deposition accounted for over 80 percent of total late season smoke deposition (August through October) in both 2022 and 2023, while wet deposition accounted for 75 and 30 percent of total early season deposition in 2022 and 2023, respectively. The largest smoke deposition events on Mount Baker coincided with precipitation events and enrichment of benzenepentacarboxylic acid, a marker of biomass burning, in snow. Using the Snow, Ice, and Aerosol Radiative model, we estimated an average albedo of 0.68 ± 0.03. The resulting instantaneous radiative forcing attributable to the presence of BC in snow ranged from 3 to 16 W/m2, with an average of 7.47 ± 3.3 W/m2.
547. Gilbertson et al. (2026) LiDAR accuracy on North American mountain summits
     Mountainous terrain is increasingly being measured and mapped by airplane-based LiDAR (Light Detection and Ranging) techniques, but the accuracy of these measurements in such topographically variable terrain is not well understood. For this study, we measured 179 mountain summits with differential GNSS static surveys and compared summit elevation and location measurements to those measured by LiDAR in point cloud data sets. We measured summits in 13 US states (Washington, Idaho, Montana, Utah, California, Nevada, Arizona, New Mexico, Michigan, Wisconsin, Kentucky, Colorado, and Pennsylvania) and two Canadian provinces (British Columbia and Nova Scotia). Summits included icecapped peaks, open rocky peaks, and tree-covered peaks ranging in elevation from 490 m to over 4000 m. LiDAR-point-cloud-derived summit elevations and locations were computed using four different methods: manual processing, highest ground return, highest return, and Lastools reclassification. The average one-sigma LiDAR vertical errors for each method were 0.50 m, 1.09 m, 9.83 m, and 1.96 m, respectively. Average one-sigma horizontal errors were 3.03 m, 2.41 m, 5.17 m, and 3.78 m, respectively. Errors are also presented separately for each type of summit. Error sources include sharp summits being unsampled, dense vegetation misclassified as ground, human-created structures misclassified as ground, snow/ice that can melt over time, and summit erosion over time.
546. Weiss-Racine et al. (2026) Mount Rainier Volcanic Hazard Information
     Eruptions at Mount Rainier produce lava flows, plumes of airborne volcanic ash, and avalanches of hot rock, ash, and gas—pyroclastic flows—that rush down the steep, ice-covered slopes of the volcano. Hot rock and ash ejected during an eruption can melt large quantities of snow and ice, forming huge, fast moving mudflows called lahars that travel 30+ miles, all the way to Puget Sound. Very large lahars can also form when weak and water-saturated rock high on the volcano collapses with or without volcanic activity. Learn more inside!
545. Zahir (2024) An analysis of the names for Mount Rainier
     Over the years, there have been frequent attempts to rename Mount Rainier to its Indigenous name by both Native and non-Native parties (Carson, 2010; Changing the Name of Mount Rainier?, n.d.; Herbert Hoover Petition Signature Photo, 1926; Wickersham & Tacoma Academy Of Science, 1893). Through these endeavors, it has become apparent that Mount Rainier has a variety of Native names and words associated with it written in various ways that have an assortment of meanings. The result is often a lack of clarity as to what the original, Indigenous name is for Mount Rainier, and how it should be written. In this article I will present the various names and words associated with Mount Rainier and their written forms. I will then present etymological (grammar) and diachronic (historical evolution) analyses for these names. I will then discuss metaphorical meanings that have attached to these words that reflect the First People’s cultural narratives and world view of Mount Rainier.
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.

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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