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North American winter season (Nov-Mar) 500 mb geopotential height classification scheme, 1979-2018

Citation

Schauer, Andrew (2020), North American winter season (Nov-Mar) 500 mb geopotential height classification scheme, 1979-2018, Dryad, Dataset, https://doi.org/10.5061/dryad.12jm63xw6

Abstract

This dataset comes from a study that investigated the link between atmospheric circulation patterns and deep persistent slab avalanches for three study sites in the western United States: Bridger Bowl, MT; Jackson Hole, WY; and Mammoth Mountain, CA. We used Self-organizing maps to generate 20 synoptic types that summarize the primary modes of atmospheric variability for 5,899 daily 500 mb geopotential height charts on record for the  North American winter season (Nov. 1 - Mar. 31) from 1979-2017. We summarize median daily precipitation totals, daily maximum, and daily minimum temperatures observed for each synoptic type, and identify circulation patterns that occur frequently during Nov.-Dec of seasons that recorded unusually high deep persistent slab avalanche activity. We also find specific synoptic types that occur more frequently in the days immediately prior to deep slab events. This work provides practitioners with a better understanding of the processes leading to deep persistent slab avalanches, thus improving our ability to anticipate these difficult to predict events. Furthermore, we provide a conceptual model to apply this study at any site faced with similar hazard, and equipped with long-term meteorological and avalanche records.

Methods

Atmospheric data was provided by the NOAA/OAR/ESRL PSD, Boulder, Colorado, USA, from their website at https://www.esrl.noaa.gov/psd/. The classification scheme was generated using self-organizing maps, implemented with the kohonen package in R. 

Usage Notes

This dataset contains 20 synoptic types that summarize the main modes of atmospheric variability over North America during the winter seasons (Nov. 1- Mar 31) from 1979-2018. We used Self-organizing maps to classify daily 500-milibar geopotential height maps on a 2.5 x 2.5 degree grid extending from 20N to 70N and 160E to 60W.