A snowfall climatology of the Ohio River Valley, USA

Snowfall in the Ohio River Valley, USA, presents a relatively unique challenge due to the large gradient of event frequency and magnitude, and subsequent levels of preparation within local communities. Even relatively small magnitude events can cause widespread impacts due to available infrastructure. Here we present a climatology of snowfall conditions and events over a 74-year period using a network of daily observational stations across the region. Snowfall totals and event frequencies both exhibit a southwest to northeast gradient of increasing snowfall, where the majority of snowfall (> 80%) occurs during the core winter months of December through February. There is a clear influence of Lake Erie on snowfall conditions in the northeast corner of the domain, where snowfall frequency, totals, and trends are substantially higher within the lake belt relative to areas further inland. Over time, snowfall significantly increased downwind of Lake Erie by as much as 42%, while significant decreases of over 55% occurred in central Tennessee and eastern Ohio. Intra-seasonally, snowfall totals trended significantly less during November and March for much of the domain, suggesting a compression of the snowfall season to more core winter months. Trends in snowfall frequency were apparent for many sub-regions, however evidence here suggests the trends in snowfall totals were primarily driven by trends in snowfall magnitude per event.