Regionalization of snowfall frequency and trends over the contiguous United States

Abstract

This study examines the regional variations in the frequency of snowfall across the conterminous United States from 1930 to 2007. Principal components analysis and cluster analysis are used to group stations together based on the main modes of variation in snowfall frequency. Results indicate the existence of seven unique snowfall regions, which correspond to predominant storm tracks across the United States. These are the southeast, the south central Plains and southwest, the Ohio River Valley and mid-Atlantic, the Pacific Northwest, and three sub-regions in the Upper-Midwest. Quantile regression reveals that the distribution functions of each region's snowfall frequency are different and in some regions, changing over time. The northern part of the Upper-Midwest is experiencing increasing trends in all percentiles of snowfall frequencies, the Pacific northwest is experiencing declines in greater than median snowfall frequencies, and the southeast is seeing a decline in extreme frequency years. Correlation analysis between large-scale teleconnection patterns and regionally averaged snowfall frequencies corroborate previous findings and indicate specific forcing mechanisms for snowfall frequency in each region.

Changes in Andes snow cover from MODIS data, 2000–2016

“…In the tropics, El Niño conditions relate to low precipitation and warmer air temperatures, whereas in higher latitudes El Niño relates to higher precipitation and warmer temperatures ). Our results suggest that this ENSO influence on temperature and precipitation most affects snow patterns north of 30 • S. The trends of decreasing P and increasing T we found in these latitudes are generally consistent with previous studies (Vuille and Bradley, 2000;Bradley, 2004;Quintana, 2012;Salzmann et al, 2013;Kluver and Leathers, 2015). South of 35 • S, SAM is the climate index best correlated with SP.…”

Changes in Andes Mountains snow cover from MODIS data 2000–2014

“…Our results suggest that this ENSO influence on temperature and precipitation most affects snow patterns north of 30°S. The trends of decreasing P and increasing T we found in these latitudes are generally consistent with previous studies (Vuille and Bradley, 2000;Bradley, 2004;Quintana, 2012;Salzmann et al, 2013;Kluver and Leathers, 2015). South of 35°S, SAM is the 15 climate index best correlated with SP.…”

Winter climate variability in the southern Appalachian Mountains, 1910–2017

“…One explanation for these spatial differences are the synoptic patterns commonly associated with snowstorms in the SAM. For the eastern regions and foothill locations, gulf low storms, such as Miller A systems, are the dominant contributor to snowfall amounts and are much more prominent during El Niño patterns (Kluver and Leathers, 2015). While western regions and high elevation locations also benefit from Miller storms, a majority of the annual snowfall seen in these areas comes from NWFS events (Perry et al, 2007).…”

“…Declines in snowfall and snow cover have been observed in many regions of the continental United States since the start of the 20th century (Kunkel et al, 2016), with statistically significant decreases documented in the SEUS since 1930 (Kluver and Leathers, 2015). Some climate models suggest that most of North America will likely see further declines in both seasonal and annual snowfall by the end of the century (Krasting et al, 2013).…”

“…States since the start of the 20th century (Kunkel et al, 2016), with statistically significant (p < 0.05) decreases documented in the SEUS since 1930 (Kluver and Leathers, 2015). The observed winter climate variability and change from other regions, along with the economic benefits that the winter season provides for many in the southern Appalachian Mountains, highlights the importance of investigating variability and change in the SAM.…”