Notwithstanding the provisions of RCW 46.10.460, it shall be lawful to operate a snowmobile upon a public roadway or highway:
Where such roadway or highway is completely covered with snow or ice and has been closed by the responsible governing body to motor vehicle traffic during the winter months; or
When the responsible governing body gives notice that such roadway or highway is open to snowmobiles or all-terrain vehicle use; or
In an emergency during the period of time when and at locations where snow upon the roadway or highway renders such impassible to travel by automobile; or
When traveling along a designated snowmobile trail.