The people at Urgences-Santé are advising people in Montreal and Laval not to venture out Monday night, unless they have to.
The temperature is plummeting significantly, which will turn all of Sunday night and Monday's rainwater into ice very quickly.
All of this will be accompanied by high winds.
The ambulance service is reporting an increase in the number of calls for pedestrians slipping and falling, and for minor road accidents, due to the icy conditions.
There are no serious injuries to report so far.
"All our resources are actively responding to the numerous calls, which are being prioritized based on their level of urgency," the ambulance service says in a statement. "We want to thank the public for its patients and the judicious use of its services on this critical day."