It's going to be a black Christmas at the Detroit-Hamtramck assembly plant this year. Amid rising inventory levels for the Cadillac CT6, Buick LaCrosse, Chevrolet Impala, and Chevrolet Volt, General Motors plans to shut off the lights for the rest of the year.

Blame the American consumer's rapidly changing automotive tastes.

According to The Detroit Free Press, the shutdown impacts 1,800 workers once production begins winding down on October 20th. GM anticipates a full production stop on November 13th. Of those workers, up to 200 might not return after production restarts following the Christmas break.

In a statement, GM said the shutdown is required to "help maintain more stable production" in a time of "declining overall industry volumes."

A quick check of the Automotive News Data Center shows ballooning supply of all four vehicles produced at the Hamtramck facility. While LaCrosse supply, measured at 284 days' worth on October 1st, is little changed from a month earlier, it's leaps and bounds above the healthy industry norm of 60-70 days. CT6 inventories stand at 106 days' worth, while Impala supply has grown from 45 to 67 days' worth. The Volt, which now finds itself outsold by its all-electric Bolt sibling, showed a 107-day supply as of October 1st, up 10 days' worth from September.

Awash with large sedans at a time when consumers can't get enough crossovers and SUVs, Hamtramck's plight mirrors that of other traditional car-producing plants. Models like the LaCrosse and Impala are no longer the sales juggernaut they were just a decade ago.

In 2007, Chevrolet's Impala pulled in over 300,000 U.S. buyers, but year-to-date sales are already well below 2016's tally - a year sales dropped below the six-figure mark for the first time. LaCrosse sales dropped 42 percent in September, year-over-year. (That September 2016 sales figure represented a 51-percent drop from 2015.) Cadillac's CT6, which went on sale in March of last year, saw sales drop 29 percent in September, year-over-year.

As for the technologically innovative Volt, the second-generation model saw sales fall 28 percent in September, year-over-year. Despite last year being the Volt's best sales year since its introduction, 2017's monthly sales have fallen below 2016 figures since April.

Of course, Detroit-Hamtramck is no stranger to layoffs, be it temporary or permanent. GM idled the plant for three weeks in January, with a second shift cut in March.