YELLOWSTONE NATIONAL PARK (AP) - A storm that knocked out power to most of the park complicated preparations for Wednesday's planned winter opening.

The storm Friday toppled trees onto power lines. On Sunday, Northwestern Energy crews spent part of the day flying around Yellowstone in a helicopter trying to get a fix on the outage.

Crews were able to reconnect power Sunday between Mammoth Hot Springs and Canyon Village. But because of the remoteness and difficult working conditions, they weren't able to say when power to the rest of Yellowstone might be restored.

Park officials lined up one truck capable of carrying 5,000 gallons of diesel to make a delivery to lodges and facilities at Old Faithful on Monday. The fuel will power generators.

"It's always been a challenge to get open, especially the winter season," park spokesman Al Nash said. "This just took the usual challenge and increased it by a factor of 10."

But he said officials expected Yellowstone to be ready for business Wednesday.

The Old Faithful Snow Lodge and Cabins, Snow Lodge Restaurant, Geyser Grill and Madison Warming Hut Snack Bar are all scheduled to open for the winter on Wednesday. The Mammoth Hot Springs Hotel is scheduled to open Friday, according to Yellowstone's Web site.

Despite the storm, snowpack around Yellowstone is below average. But Nash said most of the scheduled snowmobile and snowcoach routes, including the one between the West Entrance and Old Faithful, would still open Wednesday.

He said the routes south of Mammoth and through Hayden Valley were still being evaluated.