Minnesota-based retailers have reopened most of their stores in the Mid-Atlantic region, even as they continue to assess damage from Superstorm Sandy and account for all employees.

Target Corp. said all but three of the 200 stores the company shuttered on Monday in states like New York, New Jersey and Virginia are now open. Ten other stores have reduced hours, mostly due to damaged lights in the parking lots.

"Our teams are working diligently to make contact with all team members," Target spokeswoman Jessica Deede wrote in an e-mail. "Given the large number of stores impacted, we anticipate this process to take place over a few days."

About 40 Target stores are still operating on backup generators. Many stores suffered damage to front doors and roofs, which are leaking water, Deede said.

Best Buy Co. spokeswoman Amy von Walter said about 35 stores are still closed or opening at later hours. The Richfield-based consumer electronics giant had initally closed 220 stores prior to the storm's arrival on Monday. 

"We are focused on reaching all of our employees and are not yet at 100 percent -- we'll continue to reach out in the meantime," Von Walter wrote in an e-mail. "Conference calls with our field teams are being held daily so we have info on what's happening on the ground -- so we can ensure they have the resources needed to reopen the stores, support our impacted employees and to serve our customers."

It's not yet clear how the storm will impact sales as Sandy struck during the last few days before Halloween. IBISWorld, an industry forecasting firm, predicted that Halloween sales would jump 10.7 percent from last year to $8 billion. In addition, retailers have started to promote Christmas-related merchandise in October.

Eden Prairie-based Supervalu Inc. closed about 170 of its East Coast stores during the height of the storm, though all but three were expected to be open by Thursday morning.

The company's Acme chain of 117 stores, which is centered in New Jersey and the Philadelphia area, closed at 6 p.m. on Monday; its Shoppers chain in the Baltimore-Washington area followed at 10 p.m., said Mike Siemienas, a Supervalu spokesman.

Shoppers outlets were open Wednesday. By Wednesday evening, all but 13 Acme stores had reopened, and 10 more were expected to open by Thursday morning.

However, three Acme outlets in New Jersey could remain closed for several days. One has water damage, and another is still unreachable due to washed-out roads, Siemienas said.

Two other Supervalu chains, Shaw's in New England and Farm Fresh in Virginia, stayed open during the storm, though some had intermittent power outages.

Staff writer Mike Hughlett contributed to this report. Thomas Lee • 612-673-4113