General Motors is to temporarily idle about 30% of its North American vehicle assembly capacity in the first quarter of 2009, taking about a quarter million units out of the production schedule.

GM said the move was due to the “ongoing and severe drop in industry sales, which were down 36% in November overall and 41% for GM”.

“The speed and severity of the US auto market’s decline has been unprecedented in recent weeks as consumers reel from the collapse of the financial markets and the resulting lack of credit for vehicle financing,” the automaker said.

Affected US plants are: Fort Wayne, Indiana, and Flint Assembly in Michigan which build trucks; Wentzville,  Missouri, which makes vans; Lansing Delta Township, Michigan, which makes SUVs; Pontiac Assembly, Michigan, also a truck plant; Spring Hill, Tennessee, SUVs; Fairfax Assembly in Kansas, which builds the Chevrolet Malibu and Saturn Aura; Arlington Assembly in Texas, full size SUVs; Lansing Grand River, Michigan, Cadillac STS & CTS; Orion, Michigan, Malibu and Pontiac G6; Detroit-Hamtramck, Michigan, Buick Lucerne and Cadillac DTS; Shreveport, Louisiana, SUVs; Bowling Green, Kentucky, Chevy Corvette and  Cadillac XLR; and Wilmington, Delaware, the home of the Pontiac Solstice, Saturn Sky and Opel GT.

In Canada GM will furlough both Oshawa Consolidated (Chevy Impala) and Oshawa Truck in Ontario.

In Mexico the affected plants are Silao, which builds trucks and large SUVs; Ramos 2 (Chevy HHR, Saturn VUE, Chevy Captiva); and San Luis Potosi (Chevy Aveo, Pontiac G3).

“As a result of these assembly plant actions, GM will also continue to assess its powertrain and stamping capacity needs and make adjustments as appropriate,” the automaker said.