Few aspects of weather and weather prediction polarize people more than heavy snowfall. We love it or dread it, with equal passion. Broad segments of U.S. annual climate are defined according to winter snow's expected presence or absence. Snow is rare in the Southeast but frequents the Appalachians. Heavy snow is a wintertime staple in the Sierra Nevada and Cascades and downright crippling across the Great Lakes snowbelt. But within the zones of expectation, there is often considerable, inter-annual variation. This variability is governed by many factors, including the activity of regional-scale climate oscillations. These include the El Nino-La Nina pattern, North Atlantic Oscillation, and Pacific Decadal Oscillation. In parts of the mid-Atlantic, for instance, seasonal snowfall has been quite fickle in the past 10-15 years. Although Baltimore endured its snowiest winter on record during 2009-2010 (77 inches), it has experienced snow drought in the past three years ... with only half an inch of season-total snow as of mid-March 2023. Snowfall variation across the United States for the 2022-2023 season is shown in Figure 1. This map was released by the NOAA Weather Prediction Center during late February and captures seasonal total snow from October 1, 2022 through February 25, 2023. Per the color scale, blue tones show small amounts (several inches), while the warm colors get us into multiple-foot territory. Purple and blue show phenomenal totals in the 30-40-foot range. One can divide the United States diagonally into two broad zones: snow famine and snow feast. The northern tier and western half of the United States won the snow jackpot for this season. One does not need a terrain map of the United States to locate the principal mountain ranges across the western half, as they have been draped by 20-30-foot snow totals. In high mountains, we expect to observe seasonal amounts of this magnitude, as wintertime heavy snow accumulation is as much about altitude as it is latitude.
展开▼
