No travel is advised on Interstate 90 in South Dakota from the Wyoming border to Rapid City.
While all stretches of I-90 are open in Wyoming, drivers are urged to use caution.
Plows were busy clearing roads all day Monday and were back out early Tuesday morning to help drivers as much as possible.
Some trouble spots include construction areas started last week during nicer weather. WYDOT officials say plows faced difficulty on I-90 at Sheridan where traffic is reduced to two lanes.
"However, our maintenance personnel is taking care of that. They're going ahead and plowing those lanes, that two-lane traffic there. But really we've just reduced the speeds," said Ronda Howell, WYDOT Public Relations.
Snow and blowing conditions are still making driving dangerous across the state.