Major automakers shut down plants in six Midwest states and Ontario on Wednesday after a winter storm that swept through the region a day before cut off shipments of parts and raw materials.

Chrysler Group LLC canceled its first production shifts at plants in eight locations in Michigan, Ohio and Ontario.

General Motors Corp idled plants at six locations in four states, while Ford Motor Co temporarily shut plants in five locations.

Among the Ford closures was the Chicago assembly plant that makes the all-new Ford Explorer SUV and the Ford Taurus and Lincoln MKS sedans.

A Subaru plant in Indiana that builds the Camry sedan for Toyota Motor Co was also shut because of the storm and Toyota canceled the first shift at a plant in Princeton, Indiana, that builds the Sienna minivan, spokesman Mike Goss said.

Everything else is running right now, but it is a very fluid situation, Goss said in an email. We are monitoring suppliers.

Automakers keep few parts on hand in their assembly plants to contain inventory costs.

But the same just-in-time system for managing inventory means that they are sometimes forced to idle whole plants and thousands of workers when a single part runs short because of a supplier or shipping problem.

(Reporting by Deepa Seetharaman and Bernie Woodall, editing by Gerald E. McCormick and Maureen Bavdek)