Police released the name of three people killed

The crash shortly before 9:30 a.m. Saturday occurred in what drivers reported as whiteout conditions, with very low visibility and a lot of drifting snow, Trooper Justin Summa said.

"People were saying they couldn't see past the front bumpers of their cars," Summa said Sunday.

The major crash along one stretch of I-78 in Bethel Township involved 64 vehicles, including a dozen commercial vehicles such as tractor-trailers and box trucks, but there were also "numerous secondary crashes" behind that as traffic backed up, Summa said.

A total of 73 people were taken by four medical helicopters and by ambulance for treatment at 11 hospitals. At least one remained in critical condition Sunday, but Penn State Hershey Medical Center said two others taken to the hospital with critical injuries had improved and most of the 13 people brought to the hospital had been discharged.

The interstate reopened Sunday morning following the pileup, which left tractor-trailers, box trucks and cars tangled together across three traffic lanes and into the snow-covered median about 75 miles northwest of Philadelphia.