Highway and police officials warned drivers to add extra time to make their way on roads that still have multiple slick spots.

Metro had early morning delays on its busy Red Line because of a power outage outside the Glenmont station.

The transit agency’s bus service is running on snow emergency routes, meaning they may avoid some side streets and stops. For more details on exactly where buses are running Wednesday, riders are advised to check out wmata.com.

Metro canceled MetroAccess, its door-to-door service for those riders with disabilities, on Tuesday, because of the weather, but that service is expected to resume at noon on Wednesday.

Amtrak and MARC trains are operating on abbreviated schedules because of the weather.

Thousands of flights throughout the country have been canceled or delayed.

As of Wednesday morning at 7:30 a.m., 66 flights were canceled at Ronald Reagan National Airport. At Washington Dulles International Airport, 26 flights were canceled and at Baltimore Washington Airport 18 were canceled.

Road crews throughout the region worked overnight spreading salt and plowing major highways.

“The interstates are generally bare pavement,” said David Buck, a spokesman for the Maryland Department of Transportation. He said Interstate 270, the Capital Beltway and Route 50 “are fine and in excellent shape.”

But officials said there are still areas that are wet, snowy and icy on secondary roads and residential areas.

The Washington Post’s Capital Weather Gang said temperatures are expected to rise only into the teens by Wednesday afternoon, with winds of 10 to 20 miles per hour. The cold temperatures are expected to stick around until Saturday.

As a result, most snow and slush will not melt, and what does melt could refreeze, according to highway officials. “Overall pavement temperatures are struggling to get above 10 degrees,” Buck said, making it hard for crews to keep the roads clear of blowing snow and ice.