254. Ford (2011) The impacts of climate change at Mount Rainier National Park
     Past and future climate change Average annual temperature in the Pacific Northwest has increased 0.83°C (1.5°F) since 1920 and is projected to increase an additional 2.0-4.0°C (3.6-7.2°F), or more, by the end of the century. In addition to higher temperatures, the region will likely experience wetter winters and drier summers, with a slight increase in annual precipitation. These alterations of the climate system are due in large part to human actions, namely the emission of greenhouse gasses. Below are some of the ways Mount Rainier National Park could be affected by these changes in climate. Glaciers, debris flows and floods The Park's glaciers have decreased in area and volume over the last century in association with increasing temperatures. The retreat of the glaciers has exposed large amounts of loose dirt that can be washed into river channels during heavy rain events. Once in the channel, this dirt mixes with water to form a fast moving slurry called a debris flow. These flows can be very powerful and dislodge large boulders or trees, and also destroy riverside buildings and roads. Much of the debris washed into the Park's rivers settles out at lower elevations and accumulates on the river bed. Some areas of the Park have experienced such high rates of accumulation that the beds of some stretches of river are actually above the surrounding landscape, making it more likely for waters to overtop river banks and flood large areas of land during intense rainstorms. For example, Longmire is 8.8m (29 feet) below the bed of the nearby Nisqually River. Future temperature increases will likely lead to greater retreat of the glaciers and perhaps increased risk of debris flows and flooding. Air quality Mount Rainier's location downwind of the Seattle-Tacoma metropolitan area can lead to high concentrations of air pollutants in the Park. In fact, high elevation sites such as Paradise typically have higher average ground-level ozone concentrations than Seattle. Ground-level ozone is an air pollutant that harms humans and other organisms. Higher temperatures tend to lead to higher concentrations of ground level ozone and other air pollutants. Therefore, future warming is expected to have a negative impact on the Park's air quality. Forests The abundances and distributions of the Park's tree species are strongly influenced by climate. Thus, climate change is expected to lead to shifts in the geographic ranges of tree species within the Park. But the long lifetimes of these trees suggest that climate change induced range shifts will likely be slow in the absence of major disturbances. However, background rates of tree mortality have increased in Pacific Northwest forests, a trend thought to be caused by higher temperatures and greater drought stress. This increased mortality could alter the structure, composition and carbon storage of Mount Rainier's forests. Also, the increased temperatures and decreased summer precipitation brought about by climate change would lead to drier conditions that could increase the frequency of forest fires. An increase in fire frequency could also lead to faster shifts in tree species ranges if fires kill adult members of cool-adapted species to allow seedlings of warm-adapted species to establish. Subalpine and alpine meadows The subalpine and alpine meadows of the Park are found at high elevations where temperatures are too cold or snow covers the ground for too long for trees to grow. Over the last century, ecologists have documented tree establishment in subalpine meadows throughout the Park in association with increased temperatures. Higher temperatures and longer snow free periods in the future will likely lead to the establishment of more trees in subalpine meadows and colonization of bare ground by alpine plants, leading to an overall upward movement of these meadows. This movement will probably result in a reduction of the area occupied by the meadows, because there is less land at higher elevations, which could lead to the loss of some subalpine and alpine plant species. Whitebark pine The whitebark pines at Mount Rainier have been victim to a non-native disease called the white pine blister rust that has killed many of these trees in the Park. Climate change exacerbates the problem of the blister rust. One of these threats is a potential increase in outbreaks of the mountain pine beetle (a bark-boring insect) which can cause widespread mortality amongst whitebark pines. Although the mountain pine beetle is native to the Park, the high elevation habitats of whitebark pine have historically been too cold for beetle populations to reach epidemic proportions in most years. Rising temperatures would lead to whitebark pine stands becoming more suitable for the beetle, which could, in turn, lead to more beetle outbreaks and reduced numbers of whitebark pines. The American pika The American pika is a small mammal found at high elevations in the Park. The animal is sensitive to high temperatures and could be negatively affected by warming in parts of its range. Consistent with this expectation are observations in the Great Basin region of the Southwestern US that 10 out of 25 pika populations documented in the 20th century have apparently disappeared, and that the extinct populations were in warmer locations than surviving populations. However, pikas currently occupy locations with a wide range of average temperatures, suggesting that a large portion of the species' habitat will continue to experience suitable temperatures even with substantial warming. Pikas have also been known to adjust their behavior to cope with high temperatures by resting inside shady boulder fields during hot weather and shifting their foraging to cooler times of day. Thus, the pika will likely face threats from climate change, but may be well suited to cope with these threats.
554. Beason and Kenyon (2026) Interpreting summit elevations on Mount Rainier: Contextualizing ice-surface change, bedrock elevation, and geodetic frameworks
     Recent work has documented measurable changes in the elevation of ice-capped summits across the western United States, including Mount Rainier. At Mount Rainier, comparisons between mid-20th century survey data and modern GNSS measurements indicate a decrease in the elevation of the highest point on the mountain, driven by long-term thinning of summit ice. Here, we examine these results within the broader glaciological and geodetic context of Mount Rainier, where more than a century of observations document sustained changes in glacier thickness, extent, and mass balance. We emphasize the importance of distinguishing between ice-surface elevation and bedrock elevation when interpreting summit measurements on glaciated volcanoes, and describe how differences in vertical datums, measurement approaches, and temporal variability influence apparent elevation change. We synthesize existing datasets to demonstrate that observed elevation differences are consistent with long-term glacier thinning and are not indicative of lowering of the underlying volcanic edifice. We further highlight how terminology and framing influence interpretation of elevation change, particularly for prominent peaks where findings may be communicated beyond academic contexts. This contribution expands on recent work by providing geodetic context, integrating long-term datasets, and offering recommendations for consistent terminology and measurement practices in studies of glaciated summits.
553. Nuth and Kaab (2011) Co-registration and bias corrections of satellite elevation data sets for quantifying glacier thickness change
     There are an increasing number of digital elevation models (DEMs) available worldwide for deriving elevation differences over time, including vertical changes on glaciers. Most of these DEMs are heavily post-processed or merged, so that physical error modelling becomes difficult and statistical error modelling is required instead. We propose a three-step methodological framework for assessing and correcting DEMs to quantify glacier elevation changes: (i) remove DEM shifts, (ii) check for elevation-dependent biases, and (iii) check for higher-order, sensor-specific biases. A simple, analytic and robust method to co-register elevation data is presented in regions where stable terrain is either plentiful (case study New Zealand) or limited (case study Svalbard). The method is demonstrated using the three global elevation data sets available to date, SRTM, ICESat and the ASTER GDEM, and with automatically generated DEMs from satellite stereo instruments of ASTER and SPOT5-HRS. After 3-D co-registration, significant biases related to elevation were found in some of the stereoscopic DEMs. Biases related to the satellite acquisition geometry (along/cross track) were detected at two frequencies in the automatically generated ASTER DEMs. The higher frequency bias seems to be related to satellite jitter, most apparent in the back-looking pass of the satellite. The origins of the more significant lower frequency bias is uncertain. ICESat-derived elevations are found to be the most consistent globally available elevation data set available so far. Before performing regional-scale glacier elevation change studies or mosaicking DEMs from multiple individual tiles (e.g. ASTER GDEM), we recommend to co-register all elevation data to ICESat as a global vertical reference system.
552. Hotaling et al. (2022) Summer dynamics of microbial diversity on a mountain glacier
     Glaciers are rapidly receding under climate change. A melting cryosphere will dramatically alter global sea levels, carbon cycling, and water resource availability. Glaciers host rich biotic communities that are dominated by microbial diversity, and this biodiversity can impact surface albedo, thereby driving a feedback loop between biodiversity and cryosphere melt. However, the microbial diversity of glacier ecosystems remains largely unknown outside of major ice sheets, particularly from a temporal perspective. Here, we characterized temporal dynamics of bacteria, eukaryotes, and algae on the Paradise Glacier, Mount Rainier, USA, over nine time points spanning the summer melt season. During our study, the glacier surface steadily darkened as seasonal snow melted and darkening agents accumulated until new snow fell in late September. From a community-wide perspective, the bacterial community remained generally constant while eukaryotes and algae exhibited temporal progression and community turnover. Patterns of individual taxonomic groups, however, were highly stochastic. We found little support for our a priori prediction that autotroph abundance would peak before heterotrophs. Notably, two different trends in snow algae emerged—an abundant early- and late-season operational taxonomic unit (OTU) with a different midsummer OTU that peaked in August. Overall, our results highlight the need for temporal sampling to clarify microbial diversity on glaciers and that caution should be exercised when interpreting results from single or few time points.
551. Kincaid (2024) Using historic glacial data and GIS to predict Mount Rainier National Park's glacial future
     Will Washington state have glaciers 100 years from now (year 2124)? Due to generally warmer weather glaciers are largely in retreat globally, including the glaciers in Washington state. In Washington state summer glacial meltwater plays a vital role in the survival of wildlife and is needed for human purposes that include recreation, power generation, drinking, agricultural, and industrial. This project looked at the most resilient glaciers in Washington state, the glaciers at Mount Rainier National Park. Historic measurements were used in an exponential growth calculation to project the amount in acres each glacier at Mount Rainer will advance or retreat over the next 100 years. The glaciers were digitized into ArcGIS Pro and then adjusted according to the calculations. The results of the project show that all the glaciers at Mount Rainier should be intact in 2124. This is of vital importance to wildlife and human populations that depend on the summer meltwater for various purposes.
550. Florea et al. (2022) Fumarole-ice dynamics in cryo-speleology on volcanic edifices—Mount Rainier, Washington, USA
     The persistent fumarole ice caves nearly circumnavigating the East Crater of Mount Rainier in the Cascade Volcanic Arc in Washington, USA, are a natural laboratory to study the dynamic equilibrium between thermal flux and glacial ice. The large circum‐crater passage connects to entrances on the crater rim by steep transverse passages, and fumarole gas convection and advection maintains the cave passage distribution and morphology. Between August 2016 and August 2017, we collected hourly data using remote sondes that include temperatures at three fumarole, cave air temperature and pressure, water temperature and depth in an in‐cave meltwater lake, and the outside temperature and snow depth at Paradise Visitors Center. Correlation and wavelet analyses of these data reveal complex associations between patterns of weather, fumarole activity, and lake level. At longer scales, fumarole temperatures behave largely independently and connected to spatial and temporal changes in volcanic heat flux and glacial melt circulation. At the scale of individual storm‐events, major snowfalls seal the cave entrances, increasing cave air temperature and pressure from fumarole output and causing rising lake levels from increased melt until entrances reopen. Repeating freeze‐thaw cycles observed in the cave monitoring data are a primary cause of crater mass‐wasting.

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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