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

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.本数据集源自一项针对美国西部三处研究站点（蒙大拿州布里杰鲍尔（Bridger Bowl, MT）、怀俄明州杰克逊霍尔（Jackson Hole, WY）以及加利福尼亚州猛犸山（Mammoth Mountain, CA））的大气环流模式（atmospheric circulation patterns）与深层持久板状雪崩（deep persistent slab avalanches）之间关联的研究。本研究采用自组织映射（Self-organizing maps）生成了20种天气型（synoptic types），用以概括1979年至2017年北美冬季（11月1日至3月31日）5899张逐日500百帕位势高度图所反映的大气变率主要模态。我们统计了每种天气型对应的逐日降水总量中位数、逐日最高气温与最低气温，并识别出在记录到异常高强度深层持久板状雪崩活动的季节的11月至12月期间频繁出现的环流模式。此外，本研究还发现了在深层板状雪崩事件发生前即刻频繁出现的特定天气型。本研究有助于从业者更好地理解引发深层持久板状雪崩的物理过程，进而提升我们对这类难以预测的灾害事件的预判能力。此外，本研究还提出了一个概念模型，可在面临同类雪崩灾害且拥有长期气象与雪崩记录的任意站点推广应用本研究成果。