It’s exhausting for most individuals to think about 6 toes of snow in a single storm, just like the Buffalo space noticed over the weekend, however such excessive snowfall occasions sometimes occur alongside the jap edges of the Nice Lakes.
The phenomenon is known as “lake-effect snow,” and the lakes play an important function.
It begins with chilly, dry air from Canada. Because the bitter chilly air sweeps throughout the comparatively hotter Nice Lakes, it sucks up an increasing number of moisture that falls as snow.
I’m a local weather scientist at UMass Amherst. Within the Local weather Dynamics course I educate, college students typically ask how chilly, dry air can result in heavy snowfall. Right here’s how that occurs.
How dry air turns into snowstorms
Lake-effect snow is strongly influenced by the variations between the quantity of warmth and moisture on the lake floor and within the air a number of thousand toes above it.
A giant distinction creates situations that assist to suck water up from the lake, and thus extra snowfall. A distinction of 25 levels Fahrenheit (14 Celsius) or extra creates an setting that may gasoline heavy snows. This typically occurs in late fall, when lake water continues to be heat from summer season and chilly air begins sweeping down from Canada. Extra reasonable lake-effect snows happen each fall underneath much less excessive thermal contrasts.
The wind’s path over the lakes is vital. The farther chilly air travels over the lake floor, the extra moisture is evaporated from the lake. An extended “fetch” – the space over water – typically leads to extra lake-effect snow than a shorter one.
Think about a wind out of the west that’s completely aligned so it blows over all the 241-mile size of Lake Erie. That’s near what Buffalo was experiencing in the course of the storm that began Nov. 17, 2022.
As soon as the snow reaches land, elevation contributes an extra impact. Land that slopes up from the lake will increase carry within the ambiance, enhancing snowfall charges. This mechanism is termed “orographic impact.” The Tug Hill plateau, positioned between Lake Ontario and the Adirondacks in western New York, is well-known for its spectacular snowfall totals.
In a typical yr, annual snowfall within the “lee,” or downwind, of the Nice Lakes approaches 200 inches in some locations.
Residents in locations like Buffalo are keenly conscious of the phenomenon. In 2014, some components of the area acquired upwards of 6 toes of snowfall throughout an epic lake-effect occasion Nov. 17-19. The burden of the snow collapsed tons of of roofs and led to over a dozen deaths.
Lake-effect snowfall within the Buffalo space is often confined to a slender area the place the wind is coming straight off the lake. Drivers on Interstate 90 typically go from sunny skies to a blizzard and again to sunny skies over a distance of 30 to 40 miles.
The function of local weather change
Is local weather change taking part in a job within the lake-effect snow machine? To an extent.
Fall has warmed throughout the higher Midwest. Ice prevents lake water from evaporating into the air, and it’s forming later than previously. Hotter summer season air has led to hotter lake temperature into fall.
Fashions predict that with further warming, extra lake-effect snow will happen. However over time, the warming will result in extra of the precipitation falling as lake-effect rain, which already happens in early fall, reasonably than snow.
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