Authors: Elaina Reck*, University of South Carolina, Lilian Hutchens, University of South Carolina, Cary Mock, University of South Carolina
Topics: Paleoenvironmental Change, Climatology and Meteorology, Physical Geography
Keywords: Historical Climatology, US West Coast, Mexican War, Little Ice Age
Session Type: Poster
Presentation File: No File Uploaded
This study utilizes daily and sub-daily documentary and historical data for the US West Coast to reconstruct the characteristics of storms during the 1846-1847 winter. Documentary data sources include six different personal diaries, about thirty US and UK navy ship logs, Hudson’s Bay Company records, and several different newspapers. The navy ship logbook data were mostly at hourly resolution that included well-standardized barometer data. All the data were taken from original primary sources at historical repositories and archives, and they were transcribed into digital files. Plots of bar graphs, qualitative analyses of storm and precipitation descriptions, and rain day counts were conducted for the November 1846-April 1847 period. Regression analyses for selected stations on rain days versus rain amounts reveal quantitative seasonal precipitation reconstructions. Results suggest that the 1846-1847 winter, particularly in California, was very abnormally severe, with high intensity storms and atmospheric rivers being clearly comparable with other well-known severe winters such as 1861-1862 and 1997-1998. Some of the navy log barometric observations show record-low values as compared to modern climate ranges. The historical weather data broadly agree with tree-ring reconstructions on positive precipitation anomalies and late Little Ice Age climate but show some differences concerning spatial variability and intensity. These weather results provide a strong quantitative assessment on winter severity as related to the famous Donner Party disaster and military events during Mexican War such as the Battle of San Pasquel.