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Storm Moving through the South; Pacific Storm to Impact the West this Weekend

A storm is expected to develop over the southern High Plains today and track to the Mid-Atlantic through Friday with showers and thunderstorms. On the northern edge, snow, ice, and/or a wintry mix is possible over the central Plains. A significant storm is expected to arrive late Friday through the weekend with rain, heavy mountain snow, and gusty winds for much of the West. Read More >

Intense Lake Effect Snow Band Causes 75-Vehicle Chain Reaction Pile-Up
February 7, 2003

One person was killed and 47 people hurt, including six seriously, when a sudden snow squall swept over Interstate 94 near Benton Center, Michigan, in Berrien County, at 1:30pm, causing a large chain reaction accident.  Vehicles were strewn about both carriageways of the busy Chicago-Detroit link for a mile and a half, and closed down a nearly 12-mile stretch of the expressway for over 10 hours.  Some vehicles caught fire during the whiteout, and some were so badly damaged that the cars had to be cut apart to extract the occupants.  One woman was trapped in her truck for two hours.

The intense band of snow that caused the deadly conditions was part of a system meteorologists call a "mesolow".  This mesolow was able to concentrate the snow into a powerful, narrow band and sweep it through extreme southwest Michigan.  Snowfall rates were as high as two inches per hour within the band, with total accumulations up to a foot.  Winds were around 20 mph.

The Northern Indiana office of the National Weather Service issued a Lake Effect Snow Warning for Berrien County at 11:30am, two hours before the crash.

The graphic below shows how one of the National Weather Service's computer forecast models predicted the mesolow.  The center of the low is represented by the red "L" over northwest Allegan County.  Wind barbs and streamlines show how the wind swirled in a counterclockwise direction around the low, and converged at the center. 

mesolow

The next two pictures are radar images of the snow bands that were spiraling around the low.  The first picture was captured at the time the accident occurred.  The band of very heavy snow, represented by the white and purple colors, was moving southeastward through Berrien County.

snow     snow