Assessing The Impact of Global Warming on Glacial Elevation of The Bolam Glacier

Mount Shasta, a large stratovolcano in northern California, contains the southernmost glacial system in North America (41.3 degrees N, about the latitude of Rome). Due to its southern position, this glacial system is very vulnerable to climate warming. However, previous research indicated that this glacial system experienced significant growth during the second half of the twentieth century, mainly as a result of the so-called "snowgun effect" at high elevations, operating in the warmer, wetter winters of this ocean-influenced climate (Howat & Tulaczyk, 2005 & Howat et al., 2006). New results indicate recent, significant glacier collapse as a result of continued climate warming leading to increased ablation, which eventually overwhelms the effect of increased snow deposition at high elevations. The Hotlum, Bolam and Whitney glaciers reside on the North face of Mount Shasta while Konwakiton and Wintun reside on the South face. It is evident that glacial bodies have receded in this time period, but a more indepth inspection of the effects of climate change on the Bolam Glacier was deemed necessary. The glaciers within Mount Shasta provide a small percentage of water to the Shasta Reservoir. More notably, the glacial bodies provide water supply to support habitats for immense biodiversity in flora and fauna within the region, including endemic species. Changes in glacial terminus elevation of the Bolam Glacier were observed in the field and through aerial photography. Through topographic and photographic inspection, in field geolocated waypoint collection and analysis of field data, a retreat of nearly 1500 meters at the Bolam Glacier was observed between the years photographs of 1998 and of 2024, suggesting a significant impact on glacial bodies in the region due to changes in climate.

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