The National Weather Service issued a winter storm warning at noon today for Allegheny, Beaver and Westmoreland counties and for Hancock and Brooke counties in West Virgnia.

One to three additional inches of snow is forecast between noon and 7 p.m. By then, the region will have accumulated about 7 inches at a rate of a half inch of snow per hour.

Between 3 and 5 p.m., freezing rain and sleet are predicted, so the service cautioned drivers to drive slowly. Some of that altered precipitation already had been reported in the city just before 1 p.m. today.

What may be the heaviest snowfall of the season in the Pittsburgh area caused school closings and delays, and traffic nightmares for commuters this morning.

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And those problems continued into the afternoon. Fender benders, some of them resulting in serious injuries, were reported all over the region today.

Interstate 70 westbound, just east of the Bentleyville Exit 32B, will be closed until about 4 p.m. today because of a tractor-trailer accident, PennDot spokeswoman Valerie Petersen said.

Traffic is being detoured off of Interstate 70 at Exit 35 onto Route 481.

Police and hazmat crews were at the scene and the interstate will reopen it after it is cleared.

At 2:40 p.m., a multi-vehicle crash occurred on the inbound Parkway East on the city side of the Squirrel Hill Tunnels near the Saline Street on-ramp. Two lanes were blocked and traffic was using the shoulder and ramp to get past.



PennDOT also announced it would not be able to open the high occupancy vehicle lanes on the Parkway North for this evening's rush hour. Crews were busy addressing main arteries this afternoon and were not able to clear HOV lanes in time. The HOV lanes should be open for inbound traffic tomorrow morning, weather permitting.

Serious accidents also were reported around noon on Reedsdale Street near the West End Bridge on the North Side, and not far from there on Route 65 near Marshall Avenue in Brighton Heights.

In that second accident, a tractor-trailer reportedly lost control and drove on top of several vehicles, according to police dispatchers.

The weather also was cause for the closure today of the Pittsburgh Public Schools, and many suburban districts are closed for the day or are operating on delayed schedules. High school basketball playoff games are postponed.

See the listing of school closings and delays on KDKA.com, the Post-Gazette's news partner.

Point Park University, including its Children's School, was closing at 2 p.m. today, and evening classes are canceled. Duquesne University is canceling all activities and classes after 3 p.m. Duquesne updates are available at 412-396-1700.

Allegheny County closed all divisions of Common Pleas Court, including district judge offices, as of 2 p.m. Carnegie Library of Pittsburgh said all facilities would close as of 4 p.m.

The Harris Theater, Downtown, canceled tonight's screening of "Roman Holiday," and tonight's screening in the Pittsburgh Filmmakers' Film Kitchen series was postponed until Monday. Tonight's Tim Finn show at Club Diesel has been postponed until sometime in September.

Check out the latest conditions and forecast. Commuters also can access the updated traffic conditions.