Snow is produced at upper levels in such a winter storm system, but it eventually melts into rain as it falls through a warm air layer of above-freezing temperature (of at least 1,200 feet (370 m) in-depth) associated with the overrunning.

At the same time, a high pressure center was sitting farther north in Labrador, keeping an easterly flow of very cold air near the surface.

[7] An unusually strong Bermuda high pressure area was anchored over the Atlantic Ocean, which prevented these systems from moving further to the east, as most winter storms do when they pass over the Great Lakes–St.

Exacerbating the problem was a steep drop in temperature that immediately followed the passage of the freezing rain, which combined with the extreme power outages led to numerous indirect deaths due to carbon monoxide poisoning from generators and other sources as people desperately tried to remain warm.

Many power lines broke and over 1,000 transmission towers collapsed in chain reactions under the weight of the ice, leaving more than 4 million people without electricity, most of them in southern Quebec, western New Brunswick and Eastern Ontario, some of them for an entire month.

The bridges and tunnels linking Montreal with the South Shore were closed because of concerns about weight tolerances or ice chunks falling from the superstructures.

Cities such as Ottawa, Smiths Falls, and other Eastern Ontario municipalities, that had never experienced such an amount of freezing rain, declared a state of emergency.

On January 7, Ontario, Quebec, and New Brunswick called on the help of the Canadian Forces, prompting the deployment of more than 15,000 military personnel at the peak of the crisis.

[12] The loss of electrical power also greatly affected pig and cattle farmers, as they could no longer provide water or adequate ventilation to their barns full of livestock, leading to the death of many animals.

Military engineers and technicians worked around the clock with hydro and telephone crews to repair and replace downed transmission towers and utility poles.

[citation needed] At the height of this crisis, Operation Recuperation involved 15,784 deployed personnel (including 3,740 Reservists) from all three CF commands: 10,550 in Quebec, 4,850 in Ontario and 384 in New Brunswick.

In addition, 6,200 CF members and DND employees working at their regular jobs provided the logistical support required to sustain the operation.

Researchers at McGill University set up the project in the immediate aftermath of the disaster, finding 178 families to participate; some of the women were still pregnant at the start of the investigation.