In the shot from the sky of Wolverine's trailer, the road is completely cleared of snow. Then in the very next scene where he tells Rogue to leave, the road is covered in snow.
Ever lived up North in a normal winter? It's perfectly normal for one section of road to be covered in packed snow and another to be clear. It's perfectly normal for a 20-foot section of road to be covered in packed snow and the rest of the highway to be clear.
If I remember correctly, (it's been a while since i saw it), shortly after Logans truck flips, and he's attacked by Sabertooth, Storm creates a miniature blizzard...but then that might have been a little while after the scene you're referring to...