A classification scheme for identifying snowstorms affecting central New York State

Abstract

The Great Lakes region experiences anomalously high seasonal snowfall totals relative to similar latitudes. Although lake‐effect snowstorms are common in this region, snowfall occurs from a variety of storm types. This study examines snowstorms in a subsection of the Lake Ontario basin to develop a classification scheme to categorize the different types of snowstorms affecting the region. From 1985 to 2015, there were 11 different snowstorm types to affect the study area. The classification system was used to assess the frequency of, and snowfall produced by the different storm types within the eastern Great Lakes region. From the classification, snowstorms were categorized as either non‐direct cyclonic storms (NDCS) or direct cyclonic storms (DCS). Lake‐effect snowstorms, a type of NDCS, were the most frequent storm (35.1% of all storms) and accounted for approximately 39.4% of the snowfall. Most lake‐effect storms (37.7%) produced moderate snowfall totals (10.2–25.3 cm), yet heavy snowfall storms (≥25.4 cm) contributed significantly (ρ ≤ .05) more to seasonal snowfall totals than lighter snowfall storms. Direct cyclonic clippers forming over high latitudes of northwestern Canada, were the most frequent DCS in Central New York (11.3% of all storms), with nearly three quarters of the storms originating over Alberta. These storms only contributed 9.2% of the seasonal snowfall in the study area, compared to 12.7% from direct cyclonic Nor'easters forming near the east coast of North America. Although Nor'easters occur less frequently than clippers, when they do occur, they tend to produce heavy widespread snowfall across the region. The classification system proposed can be modified to accommodate snow basins across the globe. Classifying snowstorms will help determine the seasonal snowfall contribution from different storms and aid in future climate predictions, as individual snowstorm types may respond differently to a warming global climate.

The Seasonal Snowfall Contributions of Different Snowstorm Types in Central New York State

“…Eichenlaub (1970) suggests that lake-effect storms contribute at least 20% of the seasonal snowfall in areas lee of Lake Superior and Lake Michigan. This estimate is modest, compared to those from other studies that suggest contributions are closer to 50% in other subregions of the Great Lakes basin and during more recent years (Kelly, 1986;Braham and Dungey, 1995;Liu and Moore, 2004;Hartnett, 2020;Pettersen et al, 2020;Suriano and Wortman, 2021).…”

“…Seasonal snowfall contributions were determined by identifying every snowstorm to influence central New York State (Figure 1) from the 1995/96 to 2014/15 cold seasons (October to May). Snowstorms were identified using data from the National Weather Service's Cooperative Observer Program (COOP) and are defined as any storm in which at least 0.1 cm of snow was observed for at least two of the two-hundred and two reporting stations within the study area (Perry et al, 2007;Hartnett, 2020; Figure 2). Using the methods outlined by Hartnett (2020), a storm was considered independent from other events if there was at least a 6-h gap in precipitation (e.g., 6-h gap in 15min precipitation records and/or radar) anywhere within the study area.…”

“…Some of the snowiest regions within the Great Lakes basin are found to the lee (downwind) of Lake Ontario, including the Tug Hill Plateau of New York State (further referred to as the Tug Hill). Using different approaches, the recent studies of Hartnett (2020) and Suriano and Wortman (2021) suggest that lake-effect snowstorms account for ∼35-42% of the snowstorm events to the lee of Lake Ontario, yet contribute between 42 and 48% of the seasonal snowfall. The percent contribution is even greater within the Tug Hill, as Veals and Steenburgh (2015) estimate that lake-effect snow accounts for ∼61-76% of the mean cool-season snowfall.…”

“…Suriano et al (2019) found that overrunning systems and coastal mid-latitude cyclones account for ∼55% of the seasonal snowfall in Catskill/Delaware Watershed. Hartnett (2020) found 11 different snowstorm types that contribute to seasonal snowfall totals in central New York State. These storms included clippers, Colorado lows, frontal storms, Great Lakes lows, Hudson lows, lake-effect snowstorms, Nor'easters, Oklahoma hooks, Texas hooks, tropical cyclones, and upper atmospheric disturbances.…”

Inter-annual Variability of Snowfall in the Lower Peninsula of Michigan

“…Changnon (1968) calculated a 30% increase for the same region and a much higher increase (∼50%) for northwestern Michigan. Hartnett (2020) classified snowstorms affecting central New York into non-direct cyclonic storms and direct cyclonic storms and found that lake effect storms contributed to ∼39.4% of total snowfall for the period of 1985. Hartnett (2020 also suggested that heavy snow storms (>25.4 cm) contributed to more than 50% of total snowfall for every type of snowstorms.…”