In New Brunswick, the westbound part of Highway 2 near Sackville is only open to one lane of traffic due to a collision. Earlier Sunday, the westbound section of the road was closed.
Several other roads were shut down in New Brunswick, including the causeway between Moncton and Riverview.
The Confederation Bridge which links New Brunswick and P.E.I. is closed to all traffic. The closure came into effect at 1:45 p.m.
In P.E.I., RCMP are advising people to stay off the roads unless they need to be.
In Prince County, the provincial transportation department has taken its plows off the secondary roads.
Route 1 from Stratford east is closed because of multiple accidents.
In Nova Scotia, there were two multiple-vehicle crashes on Highway 102.
Police and fire officials responded to a seven-vehicle collision in Milford near exit 9.
Cpl. Andrew Joyce says injuries are minor in nature, but some vehicles have been extensively damaged.
RCMP are also responding to a 10-vehicle collision in Upper Onslow at exit 15. Police say several vehicles are off the road there.
Both southbound lanes at the exit are closed, while the northbound lanes are moving very slowly.
Provincial transportation department officials are also urging people to be cautious.
The poor weather conditions are impacting flight plans across the Maritimes.
At the Halifax Stanfield International Airport and the Charlottetown Airport, many flights in and out of the airport are delayed or cancelled.
In New Brunswick, there are some delayed flights at the airports in Fredericton, Moncton and Saint John, but nowhere near to the extent of what is happening in Nova Scotia and P.E.I.