U.S. & World

NEW YORK (CBS News) ― Commuters are facing a slow and slippery commute as the latest winter storm brings a messy mix of precipitation to New England.

What began as snow was expected to gradually change over to sleet and rain in Massachusetts. By early Wednesday, the change had already occurred in the immediate Boston area and along the coast. But snow continued to fall in areas north and west of the city where temperatures remained below freezing.

Plows were out in force overnight but conditions were icy or slushy on many highways and secondary roads. The speed limit on the Massachusetts Turnpike was reduced to 40 mph.

Many school districts delayed or canceled the start of classes.

Another concern was the potential for flooding once the precipitation changes over to all rain. Forecasters predicted between 1 and 2.5 inches of rainfall in southern New England, and the National Weather Service said a flood watch was in effect through early Thursday.

Further south, an ice storm warning was scheduled to end at 7 a.m. in Washington D.C. and two nearby counties in Maryland, Prince George's and Charles.

To the north and west of the District, ice storm warnings were in effect until 11 a.m. in Howard, Montgomery and Frederick counties.

Pepco was reporting 28,500 outages in Prince George's and Montgomery counties, but only a handful of outages in the District. Dominion Power was reporting more than 11,000 outages in Northern Virginia.

Winter's latest delivery of misery tied up travel and snarled primary-day voting all along the East Coast on Tuesday after icing over parts of the Ohio Valley.

A bridge over the Delaware River near Philadelphia closed during evening rush hour so crews could spread salt, and speed limits were lowered on others.

"Things got ugly really quickly," said New Jersey State Police Sgt. Stephen Jones. Vehicles slid off Interstate 295 in southern New Jersey, and other highways were shut down, he said.

Maryland extended its polling hours by 90 minutes in Tuesday's primary because the weather created gridlock in areas, preventing people from voting.

In Pennsylvania, Gov. Ed Rendell extended Tuesday's deadline for political candidates to qualify for the state's April 22 primary until noon Thursday, citing weather concerns.

The system also dropped snow in the Midwest, where more than 400 flights were canceled and all were delayed at Chicago's busy O'Hare International Airport. In Michigan, highway officials got edgy as their supplies of road salt dwindled.

"We've got a couple hundred tons being delivered today, but it's getting pretty low," said Mark Sohlden, engineer-manager of the Gladwin County Road Commission. "The way the winter has been so far, we've pretty much exhausted a lot of our supply."

Winter storm warnings were posted from western Tennessee into New England as the storm left the Ohio Valley, where thousands lost power and at least four people were killed in traffic accidents.

A highway in western Kentucky was closed after ice-laden trees fell from a bluff and damaged passing cars, transportation officials said. Louisville police reported more than 250 vehicles abandoned in Jefferson County.

Schools were closed Tuesday in parts of Kentucky, Illinois, Indiana, Ohio, West Virginia and Pennsylvania. Classes at Southern Illinois University were canceled by the weather for the first time since the 1980s.

Two people died in Kentucky after their car slid off an icy highway. At least two traffic deaths, along with dozens of injuries, were reported in Missouri.

The Weather Service also issued flood warnings in some parts of Kentucky. Police in the state's western tip said several roads were closed by rising water.

Farther to the south, winter was not the problem; wind was.

Strong storms produced hail, damaging winds and possible tornadoes from Louisiana to Florida, spawning a tornado that killed a woman near New Orleans and winds that upset a moored ship on the Mississippi River.

The storms followed catastrophic weather in the South last week that produced the deadliest tornado outbreak in years. The Tennessee Emergency Management Agency on Tuesday reduced that state's death toll from the storms by one, to 31. That puts the overall toll from the storms at 56.

(© 2009 CBS Broadcasting Inc. All Rights Reserved. This material may not be published, broadcast, rewritten, or redistributed. The Associated Press contributed to this report.)