West Yorkshire Police said the closure between junctions 21 (Milnrow) and 24 (Ainley Top) follows three high-sided vehicles overturning due to high wind speeds and driving snow.
Chief Inspector Ian Williams said: “We have got 4km of traffic stuck in both directions. We are working with Greater Manchester Police, Highways England, local authorities and other emergency services to turn these vehicles around.
It follows reports of drivers being stuck for more than 10 hours due to a series of incidents on the motorway across the Pennines.
Chf Insp Williams said: "If anyone is in urgent need of assistance they are asked to phone 101 to ensure that our operators can prioritise getting help to anyone with a particular vulnerability or issue sooner.
“Please be assured that we are working hard to get everyone moving.”
Drivers are urged to check the Highways England website and follow the WYP_CCC Twitter account for regular updates on road closures throughout the Force area.