Great Lakes region preparing for bad weather as lake-effect snowfall ingredients begin mixing

DETROIT (AP) — It’s that time of year — again — when cold air sweeps across the Great Lakes region, dropping huge amounts of lake-effect snow from Michigan’s Upper Peninsula into Western New York.

Snow has already started falling Wednesday in and around Houghton, Michigan, and is expected to continue through Thanksgiving and into the weekend. A blizzard warning is in effect through Thursday morning in the Keweenaw Peninsula where Houghton is located, according to the National Weather Service.

“The system coming through is producing some snow,” said Steve Considine, a meteorologist with the National Weather Service in Michigan’s White Lake Township northwest of Detroit. “Most is enhanced off the Great Lakes — snowbelt areas. That’s where they are looking at the big snowfall.”

The western part of Michigan’s Upper Peninsula also is under a blizzard warning with heavy snow and strong winds, Considine said, adding that the northern Upper Peninsula could see accumulations of a foot to three feet (0.3 to 0.9 meters) of snow with most of that lake-effect.

But what causes lake-effect snow?

It typically starts north of the U.S. border

When cold air, often from Canada, blows over the Great Lakes it can spell weather trouble for Michigan, Ohio, New York and other states in the region.

Warming air from the lakes pushes the moisture in the sky higher into a zone most conducive to snowfall because of its temperature. Clouds capable of dumping heavy precipitation downwind then form.

“You need open water on the Great Lakes, preferably fairly warm water temperatures in the 40s,” Considine said.

Most of the moisture needed for lake-effect snow does not actually come from the lakes, but rather from cold air that blows over them. Add a fairly stationary wind direction and the right conditions can be created for heavy snowfall.

Temperatures Wednesday night in Houghton were expected to dip into the low 20 degrees Fahrenheit (7 degrees Celsius) and are forecast to remain below freezing through Saturday.

Amount of snowfall can vary

From that typically comes thin bands of clouds that can produce heavy snowfall — 2 to 3 inches (5 to 8 centimeters) per hour and sometimes more. Because the bands are narrow, snowfall can vary from place to place.

The Kalkaska area in Michigan’s northwest Lower Peninsula possibly could see more than a foot (.30 meters) of snow. However, Grand Rapids, Michigan, which is just east of Lake Michigan, could see 2 to 5 inches (5 to 12 centimeters) inches of snow, while nearby Kalamazoo may get 4 to 8 inches (10 to 20 centimeters).

Lake-effect snow from the current storm system moving through Michigan “loses its intensity as it pulls away from Lake Michigan,” Considine said.

Buffalo “king” of lake-effect snow

Other very large lakes, including the Great Salt Lake in Utah, can experience lake-effect snow, but its fury is more common along Lakes Superior, Michigan, Huron, Erie and Ontario.

Communities off of Lakes Erie and Ontario, to the east, could get walloped by the current storm system. A wide stretch of western New York already is under a lake-effect snow warning.

Buffalo’s temperature was expected to dip into the low 30s Wednesday night, according to the weather service and remain in the 30s through Saturday.

A foot to 18-inches (30 to 46 centimeters) of snow is forecast south of Buffalo, while 6 to 10 inches (15 to 25 centimeters) could fall near Watertown, New York, Considine said.

“There have been some really big events in the Buffalo area,” Considine said. “Buffalo is really the king of lake-effect. They get the band coming off Lake Erie. It’s shallow and relatively warm at the first part of winter.”

Lake-effect storms dumped more than 6 feet (1.8 meters) of snow in western New York in November 2022. The wintry storms were the worst in New York since at least November 2014, when some communities south of Buffalo were hit with 7 feet (2.1 meters) of snow over the course of three days, collapsing roofs and trapping drivers on a stretch of the New York State Thruway.