ALLENTOWN Forecasters had called for about an inch of snow to fall on the day after Christmas.

They didn't expect it to come down in a half-hour.

When it did, hundreds of motorists got stalled on major highways clogged with pileups and fender-benders.

A quick-moving squall dumped about two inches of snow around 9 a.m. Thursday in Berks County and quickly spread into the Lehigh Valley, where it dropped an inch and caused several crashes along highways.

"It caught some motorists off-guard," said Ron Young, a spokesman for the Pennsylvania Department of Transportation. "In this weather, you have to be extra ready for anything."

Young said drivers might not have been prepared for the sudden change in weather and did not slow down until it was too late.

"Mother Nature can do this," he said. "There is no control over the weather. If there is a snow squall or a sudden blast of snow, people need to slow down and drive according to conditions."

The snow also was blamed for four Pennsylvania Turnpike accidents in southern Berks County involving 35 vehicles, including a turnpike plow truck, and possibly a fatal accident in the Poconos.

Officials also reported a smattering of crashes in Chester and Montgomery Counties.

On the Northeast Extension, there were temporary lane closures between the Mahoning Valley and Quakertown exits following accidents that occurred north and south of the Lehigh Valley interchange.

A series of morning accidents on I-78 in Greenwich Township closed a five-mile section of the westbound lanes between the Krumsville and Lenhartsville exits and detoured traffic to alternate routes. The road was reopened at 3 p.m.

State police said dozens of people were injured. At least 11 crashes occurred in the five-mile stretch, Trooper David Boehm said.

Renee Colborn, spokeswoman for the Turnpike Commission, said the surprise snow had little effect on the Northeast Extension, but caused a mess on the turnpike south of Reading.

Between 8:53 and 9:21 a.m., four accidents involving about 35 vehicles occurred within a 21/2-mile stretch of the turnpike between the Reading and Morgantown exits, she said.

"Nobody was killed," Colborn said. "But right now, we know that nine or 10 people were transported [to hospitals] with injuries.

"One of those accidents, the third accident, involved one of our trucks. Three vehicles hit one of our plow trucks. It was a chain-reaction kind of thing."

With so many reports coming in so quickly Thursday morning, Colborn said, she initially figured they were all about a single crash in the snow.

"First I thought it was just a fender-bender, but then within a half-hour, it escalated into four separate accidents," she said. "More information kept trickling in."

Greg Heavener, a meteorologist with the National Weather Service, said Thursday forecasts had called for about an inch of snow, but it was expected to come down over six hours.

"There was no advisory given," Heavener said. "The situation didn't really permit for one. It lasted about a half-hour."

Heavener said the snow also came down a little further south than expected, with Reading getting the heaviest snow totals with two inches. He described Reading as "the main epicenter" for the snowfall.

"We expected a light snowfall with a cold front to move through the area," he said. "It came in faster than expected and a little heavier than expected."

The weather service said 2.3 inches of snow fell in Reading, while parts of Chester County saw nearly two inches, with 1.8 inches recorded in East Nantmeal and Elverson, and 1.6 inches in West Caln.