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, which 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 e-mail. We are monitoring suppliers.

Four Honda Motor Co plants in Ohio are also closed today as well as a plant in Indiana which builds the Honda Civic sedan.

All plants made it through Tuesday OK, but today is another matter, Honda spokesman Ed Miller said.

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 they are sometimes forced to idle entire plants and thousands of workers when a single part runs short because of a supplier or shipping problem.

Now, as automakers seek to ramp up production to meet burgeoning demand, some auto suppliers are coming up short, having cut capacity during the downturn. This led to Ford and Chrysler's decision to idle plants last week.

In Canada, Chrysler's minivan plant in Windsor, Ontario, was already closed this week because of a parts shortage. Last week, Ford idled the plant where it makes its best-selling F-150 pickup trucks due to a shortage of engines that are made at a Ford plant in Cleveland.

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