The news media reports at least 3 major pile-ups on PA interstates in the northwest. I've heard that 3 were killed, but just one pile-up involved 50 vehicles. Pictures showed big trucks involved as well. (I saw one Ozark tractor) There is information on this site that should help many to survive the weather.

It's very common for 4-wheelers to slow down when they can't see because of "white-out" conditions. Traditionally, since trucks have a higher vantage point, visibility is better (as far as seeing where the road is), but it doesn't matter what size the vehicle is, powder snow will lift off the road and hide the vehicle. Judging the distance to what's in front of you becomes a chore.

The other thing that happens, is when visibility gets poor, the slowed traffic also packs down the snow instead of lifting it off the road so the breeze can blow it away. In "white-out" conditions, snow will be, both, loose, lifting, and hanging in the air... And, packed down onto the road. By the time you get to see tail lights (or even brake lights), you're too close. If those lights are brake lights, the vehicle may be nearly stopped, and if you're still moving, you're going to meet someone and exchange information.

When I was driving, I came up with a rule that if the snow was not blown away or settled back down, I was too close. I didn't make a lot of headway, but I also didn't get any fresh scratches or dents.

On the weather channel, they just said that they have "HAZMAT" on the road in Venango County, on I-80. Another major accident (pile-up) was on I-79, north of I-80. Looks like Venango and Mercer counties.

Other than that, Northern WI, MN, and ND are having issues with visibility due to heavy snowfall.

I sat on EB I-80 near Lamar, PA (about MP 186 or so) for an hour while they cleaned up some wreckage two nights ago. I guess on the west bound side there were eight cars and two FedEx doubles in the ditch. We used to say that much like seeing a robin heralds the coming of Spring (in the North), that seeing your first FedEx double in the ditch meant that Winter is here. One time a few years ago, from Albuquerque to Amarillo, we counted fourteen FedEx doubles that had run amok.

Winter driving is simple common sense. Even if the road isn’t icy, if there’s snow, you know you have less traction than if it were dry. I’ve never been worried about MY driving, but am terrified at the driving habits of others… four wheelers AND big truck drivers. There will be a couple inches of slush and snow on the road and a line of trucks will blow by me running 65 or 70 mph with only a car length between them. I’m usually one of the faster vehicles on the road in bad weather, but I keep a good distance between me and any other vehicle. I absolutely refuse to run in a pack. I also always adhere to my own policy that if it’s so bad that I can’t run at least 35 mph, then I park it until they get the roads cleaned up.