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A dramatic reconfiguration of the subalpine ecotone is underway in many mountainous regions. One of the changes occurring in subalpine ecosystems is the shrinking and fragmentation of subalpine meadows. In July 2016, we investigated the encroachment of conifers into a subalpine meadow on the south side of Mount Rainier as part of the North American Dendroecological Fieldweek, a unique experiential learning program dedicated to training participants in the theories and techniques of dendrochronology. We collected increment cores and cross-section disks from conifers in a subalpine meadow to determine their dates of establishment. We compared these establishment dates with climatic and environmental variables to assess potential drivers of encroachment. Our results show that the establishment of conifer seedlings occurred in distinct pulses over the twentieth century coinciding with periods of low summer snowfall. We found that seedling establishment rates were much higher on locally convex micro-topographic settings and in areas with a dense cover of woody shrubs. The spatiotemporal patterns of seedling establishment we observed appear to be the result of the complicated and highly scale-dependent interplay between climatic fluctuations and both biotic and abiotic microsite conditions. While our results should be considered a preliminary analysis, they reveal a compelling story of the spatiotemporal patterns of conifer encroachment and suggest potential causal mechanisms that warrant further investigation., Introduction SUBALPINE AND ALPINE ECOSYSTEMS are experiencing dramatic changes in response to the direct and indirect effects of climate change and land use practices (Parmesan 2006; Gottfried et al. 2012). [...]

The summit of Mount Rainier is attempted by up to 10,000 climbers per year. During their two-day ascents, they use either a pit or solar-assisted toilet at Camp Muir, or the snowfields for disposal of their feces and urine. Mount Rainier National Park personnel know neither the flow path directions nor the concentrations of microorganisms or chemicals from these wastes during annual runoff. This initial study attempted to determine the concentration of fecal coliforms, fecal streptococci, enterococci, E. coli, Pseudomonas aeruginosa, chloride ion, conductivity and total dissolved solids (TDS) in runoff along the most frequently used ascent route to the summit, the Muir Snowfield. During the five-week sampling period, no fecal microorganisms were found in the runoff. Although conductivity and TDS values approached those of distilled water, samples from the margins of the snowfield had values nearly twice as high as runoff sampled from fell fields within the snowfield. Computer modeling of the predicted flow paths of runoff completed after field work indicated that the main areas of runoff may be hydrogeologically different from those areas sampled. Further studies need to be completed to study the fate of feces and fecal organisms, and the flow paths of runoff contaminated by human wastes., Introduction As is typical of many of our national parks, Mount Rainier National Park has experienced a consistent increase in visitors since it was established in 1899 (1). Located in [...]

Catastrophic collapses of steep volcano flanks threaten many populated regions, and understanding factors that promote collapse could save lives and property. Large collapses of hydrothermally altered parts of Mount Rainier have generated far-traveled debris flows; future flows would threaten densely populated parts of the Puget Sound region. We evaluate edifice collapse hazards at Mount Rainier using a new three-dimensional slope stability method incorporating detailed geologic mapping and subsurface geophysical imaging to determine distributions of strong (fresh) and weak (altered) rock. Quantitative three-dimensional slope stability calculations reveal that sizeable flank collapse ([is greater than] 0.1 [km.sup.3]) is promoted by voluminous, weak, hydrothermally altered rock situated high on steep slopes. These conditions exist only on Mount Rainier's upper west slope, consistent with the Holocene debris-flow history. Widespread alteration on lower flanks or concealed in regions of gentle slope high on the edifice does not greatly facilitate collapse. Our quantitative stability assessment method can also provide useful hazard predictions using reconnaissance geologic information and is a potentially rapid and inexpensive new tool for aiding volcano hazard assessments. Keywords: landslide, volcano, debris flow, slope stability, hydrothermal alteration, Mount Rainier.

Mount Rainier is in the Cascade Mountain Range near Tacoma, Washington. Mount Rainier is one of the largest stratovolcanoes in the continental US. It is also an extremely dangerous and [...]