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  4. The unprecedented size of the 2017 wildfires that burned nearly 600,000 hectares of central Chile highlight a need to better understand the climatic conditions under which large fires develop. Here we evaluate synoptic atmospheric conditions at the surface and free troposphere associated with anomalously high (active) versus low (inactive) months of area burned in south-central Chile (ca. 32–41° S) from the Chilean Forest Service (CONAF) record of area burned from 1984–2018. Active fire months are correlated with warm surface temperatures, dry conditions, and the presence of a circumpolar assemblage of high-pressure systems located ca. 40°–60° S. Additionally, warm surface temperatures associated with active fire months are linked to reduced strength of cool, onshore westerly winds and an increase in warm, downslope Andean Cordillera easterly winds. Episodic warm downslope winds and easterly wind anomalies superimposed on long-term warming and drying trends will continue to create conditions that promote large fires in south-central Chile. Identifying the mechanisms responsible for easterly wind anomalies and determining whether this trend is strengthening due to synoptic-scale climatic changes such as the poleward shift in Southern Hemisphere westerly winds will be critical for anticipating future large fire activity in south-central Chile.
  5. Ice patches are an irreplaceable archive of past events. With atypical melting now occurring around the world, it is important to be able to quantify and interpret the potential of what remains in areas of archaeological interest. A ground-penetrating radar (GPR) survey was conducted at an archaeologically productive ice patch in the Greater Yellowstone Area to identify sediment layers in which archaeological materials may be present. Numerous reflective surfaces were observed and interpreted as being organic-rich layers called lags. GPR did not reveal all lag surfaces that were easily identifiable in an ice core that was collected concurrently at the same ice patch. 400 MHz and 900 MHz antennas were used in the survey, but neither fully revealed the basal profile of the ice patch. This is likely the result of the short time-window in which the data were collected, as opposed to attenuation of the radar waves deep in the ice. Future applications of the technology are explored.