SOUTH BUFFALO TWP, Armstrong County — A winter-style storm Sunday afternoon is blamed for a three-vehicle crash on Route 28 that sent a pregnant Butler County woman to the hospital.

State police said a sudden hail and thunderstorm precipitated the chain-reaction accident about 4:30 p.m.

The wreck happened when a Chevrolet Cobalt driven by Michael W. Aldrich, 46, of Ford City rear-ended a 2002 Chevrolet Tahoe.

The SUV, driven by Nicholas J. Welter, 26, of Donegal Township, was pushed forward and then started to slide on the wet and icy highway at the Slate Lick exit, police said.

Welter’s vehicle traveled onto the road’s east berm and hit the rear of a Chevrolet Cavalier driven by Keith J. Baer, 38, of Vandergrift, who had pulled off the highway to wait out the sudden weather conditions.

Police said the road was made slick by a combination of rain, snow and hail. The grass median divider was snow-covered and there was hail on the east and west sides of the roads, said Trooper Timothy Amy.

Katherine Ann Welter, 26, a passenger in her husband’s Tahoe, was taken to ACMH Hospital near Kittanning for precautionary reasons. Police noted that she is seven months pregnant but apparently was not hurt.

No other injuries were reported in the crash.