"Dense fog has formed over western Alberta, particularly over Highway 40, and is expected to continue before dissipating Thursday morning"
A Fog Advisory is in effect once again for Grande Prairie, Beaverlodge, Hinton and Grande Cache
Environment Canada says near zero visibility from fog is expected or occurring in parts of the region Wednesday evening, particularly over Highway 40.
"Travel is expected to be hazardous due to reduced visibility in some locations. If visibility is reduced while driving, slow down, watch for tail lights ahead and be prepared to stop"
More details here