The Curious Case of 2019: A Year of Extremes in the Black Hills

Rising above the High Plains of the north central U.S., the Black Hills have traditionally been associated with rapidly evolving, challenging-to-forecast weather based on their geographical location and unique topography. Over the first half of 2019, the Black Hills region expanded its record books in terms of temperatures, precipitation, snowfall, and flooding. In particular, May 2019 was one of the coldest, wettest, and snowiest Mays on record for the Black Hills region, culminating in a prolonged heavy precipitation event from May 20th to 22nd, bringing one to two feet of snow to some locations that had never recorded measurable snow on those dates. Rapid snowmelt combined with heavy rainfall at lower elevations also contributed to record river crests on the White River and Cheyenne River during this period, areas that had experienced near-record flooding just two months prior resulting from ice jams and snowmelt. The extremely wet early-to-mid spring set the stage for an equally active late spring and early summer as convective season began. Throughout June and July, numerous severe thunderstorm events brought additional flooding, several tornadoes, and numerous significant hail and straight-line wind events to the region. Accordingly, the Rapid City National Weather Service forecast office (NWSFO) issued 270 tornado or severe thunderstorm warnings from June 1st through July 19th, 39 more than any other NWSFO during that time period. This work will present the highlights of 2019 across the Black Hills, including an overview of the synoptic scale patterns that contributed to such a year of extremes.