Freezing rain
Episodes of freezing rain and glaze ice accumulation have a series of impacts on Quebec communities and ecosystems.
The extreme accumulation of glaze ice in January 1998 and April 2023 put a severe strain on the province’s energy sector and had consequences for the built environment and biodiversity. These events paralyzed many daily activities, both economically and socially, and had a significant impact on the physical and mental health of communities.
Impacts on health
Impacts on the agricultural sector
Impacts on the energy sector
Impacts on forest ecosystems
Impacts on buildings
Impacts on health
Physical health
Episodes of freezing rain and the accumulation of glaze ice can have many consequences on the physical health of workers and other people, and can even be life-threatening. These impacts include the risk of accidents due to hazardous road conditions and falls and injuries like hip fractures, caused by the accumulation of ice on the ground. Cases of carbon monoxide poisoning due to power outages were also reported across the province during past freezing rain events.
During the 1998 ice storm, the physical health of those affected was significantly impacted, resulting in increased demand for ambulance services, emergency room admissions and hospitalizations.
Psychological and mental health
In terms of psychological and mental health, episodes of freezing rain, particularly if they lead to prolonged power outages, can create fear, stress, disorganization and a sense of vulnerability among members of the public. In 1998, surveys revealed that 34% of those affected reported abnormally high levels of stress associated with the ice storm.
Vulnerable and/or marginalized populations
Episodes of freezing rain can have serious consequences for the physical and mental health of the entire population. Even so, the people who are most vulnerable to this phenomenon are those with pre-existing health problems, the elderly, people with reduced mobility and those with few personal resources.
Impacts on the energy sector
Over the past few decades, episodes of freezing rain have posed major challenges for Quebec’s energy sector. The accumulation of ice on power transmission and distribution lines led to the breakage or collapse of certain parts of the electrical network, resulting in power outages. The episodes in January 1998 and April 2023 were particularly noteworthy, as they had a major impact on power grids in several regions of Quebec, leaving more than 1 million customers without electricity in each case. Power outages during the 1998 crisis lasted up to 35 days in some places, while in 2023, most of the power grid was restored within three days.
The 1998 ice storm remains the event with the greatest impact on Quebec’s energy infrastructure. It brought down 1,000 steel towers and 30,000 wooden electricity poles, as well as a great number of wires and cables. The distribution network can also be affected by vegetation, such as trees, falling on power lines during icy spells.
In addition to damage to the power grid, freezing rain can lead to the creation of frost that impairs the operation of wind turbines. Frost can lead to excessive mass, necessitating a preventive shutdown of production. It can also raise accessibility issues for wind farms, given the danger to workers of falling ice.
Since climate projections suggest freezing rain events will occur more frequently north of the 50th parallel, i.e. in areas with major hydroelectric facilities, adaptation measures must be taken to limit the potential consequences. It should be noted, however, that projected climate change in the south of the province is unlikely to aggravate this risk; in fact, climate change will probably reduce it there.
Impacts on buildings
In addition to the impact of freezing rain on energy infrastructure, this climate hazard can also cause damage to buildings. Freezing rain combined with other weather phenomena, such as wind, can increase the risk of leaks in wall and roof assemblies and around openings such as doors and windows, leading to repair costs for owners.
See the page on winds and storms for more information.
Impacts on the agricultural sector
Freezing rain and heavy ice accumulation can have a number of repercussions on the agricultural sector. One of the main impacts is the disruption of farming operations in the event of power outages. Farms that depend on electricity for their production can be seriously disrupted by power failures, as happened in 1998, when more than 3,000 farms in the “black triangle” between Saint-Hyacinthe, Granby and Saint-Jean-sur-Richelieu were affected, some without power for several days.
In addition to the consequences for production, power outages due to freezing rain can have a significant impact on livestock. Most farm animals require stable light, temperature and humidity conditions. Some animals, especially pigs and poultry, are highly sensitive to variations in their usual conditions. In the event of a prolonged power failure, animals may perish, leading to significant economic losses for livestock producers.
In addition to the impact of power outages on the agricultural sector, ice build-up can damage or even destroy greenhouse structures, resulting in reconstruction costs for growers. However, as most greenhouses don’t operate during the cold season, the impact on production is generally limited.
Ice storms can also have an impact on orchards, especially apple trees. Due to ice build-up, branches can crack or break, resulting in crop losses. In 1998, an estimated 40% to 60% of apple trees in areas affected by the ice storm were damaged, leading to a reduction in apple production for the following 3 to 4 years.
Impacts on forest ecosystems
In the northeastern forest region of North America, freezing rain events are a frequent disturbance that can have an impact on forest structure, composition and dynamics. Freezing rain disrupts the growth and mortality conditions of species in different ways, depending on their ability to withstand it. Over the long term, freezing rain modifies forest composition and can create selective pressure that reduces tree species diversity in certain regions of Quebec.
In urban environments, forest ecosystems are very sensitive to freezing rain events. There, trees face additional stress factors such as more frequent pruning and cutting, shocks from snow removal (mainly for street trees), drought and pollution, making them more vulnerable to ice build-up than trees in rural areas.
Under the weight of accumulated ice, branches and even tree trunks can be broken. Freezing rain can also affect twigs and buds, resulting in slower growth the following spring and significant damage to the forest canopy. In 1998, the ice storm damaged around 80% of trees in western Quebec, necessitating pruning and even the felling of many trees to clear traffic lanes and protect the overhead power grid. Many trees suffered considerable injury, requiring treatment the following spring. In 2023, the ice storm caused more than 4,500 branches and trees to fall in Montréal. Due to the heavy ice layer, even some healthy trees had to be felled.
Trees’ sensitivity to glaze ice depends on their individual characteristics, such as species, height and diameter, as well as the properties of their wood and the stand of trees. For example, studies have shown that the yellow birch is more vulnerable to ice damage than species such as sugar maple, ash and beech, which are more resistant. Conifers, which retain their needles in winter, are generally more susceptible to ice damage than hardwoods, due to their large surface areas, which can accumulate a lot of ice. However, their sensitivity can vary depending on the species and the specific environmental conditions.
