Schuylkill County coroner Dr. David J. Moylan warned Monday afternoon that the death toll "could run higher" because the search of the scene hadn't yet been completed because of burning vehicles.
The fiery crash occurred on Interstate 81 at about 10:30 a.m. near Minersville, about 100 miles northwest of Philadelphia, John Blickley of the county's emergency management office, told USA TODAY.
Footage uploaded to social media showed an out-of-control tractor-trailer smash into a large dump truck, turning it nearly 180 degrees.
Another large truck spewed black smoke and orange flames into the air and an SUV struck a passenger car sending the sedan spinning,
The collision closed all lanes of I-81 north in Schuylkill County and highway message boards were redirecting traffic, said Ronald Young, spokesperson for the Pennsylvania Department of Transportation
Pennsylvania State Police are investigating the crash and numerous local EMS, fire and police agencies are responding to the scene, police Lt. Adam Reed said.
A number or tankers were on location to replenish water because there was no water source from hydrants.
The National Weather Service office in State College warned of snow squalls in central Pennsylvania and advised drivers to stay alert.