Assessment of Crystal Characteristics and Snowfall Impact During the North Carolina Snowstorm of 17 January 2018 (52)

Gail Hartfield, NOAA/NWS, Raleigh, NC

Frank Alsheimer, NOAA/NWS



Winter storms in the Carolinas can produce significant impacts, given that such storms typically consist of a variety of precipitation types, often mixing and changing during a storm's lifetime. But even the occurrence of a single precipitation type, such as in the snowstorm of 17 January, 2018, can cause significant problems. In this event, forecasters were confident that it would feature just snow (albeit with a rain-snow mix at onset). Predictions of snow-liquid ratio (SLR) were accurate however, the impacts were greater than anticipated. It is hypothesized that the character of the ice crystals near the ground promoted significant aggregation, which allowed for considerable accrual of snow on trees, power lines, and other elevated surfaces, leading to greater-than-expected power outages across the area due to snow-laden tree limbs.

In this presentation, we will examine several observational datasets, including upper-air soundings, dual pol radar data, GOES-East imagery and products, and surface meso-analyses, along with high-resolution model output, to assess the microphysical characteristics of this snowfall during its evolution, in an effort to better understand the factors leading to this impactful snowfall. It is hoped that the clues provided in this case will help better anticipate crystal characteristics and subsequent impacts during future snowfall events in this region.