The A417 has been closed in both directions near Cirencester, it has been confirmed.
Gloucestershire Police made the decision to shut the major route between the A46 junction and Air Balloon Roundabout at around midday today (Sunday).
The snowfall has caused an “unprecedented amount of weather related incidents including road traffic collisions”, a force spokesperson said.
Adding: “If you don’t need to go out stay home. Be sensible and stay safe.”