Another ice storm could happen. Is Hydro-Québec ready?
Utility reassures clients that impact would be far less severe if another such storm were to hit us now
Two decades after one of the worst natural disasters in Canadian history began, a climate scientist at McGill University is warning that Quebecers aren't immune from experiencing another ice storm like the one that crippled much of the province in 1998.
But Hydro-Québec reassures clients that if a similar storm were to hit, the impact would be far less severe.
As much as 100 millimetres of freezing rain fell on parts of eastern Ontario, southwestern Quebec and New Brunswick.
For those who ventured out, the sights and sounds were striking — the boom and flash of light from exploding transformers, the crack of tree branches collapsing under the weight of the ice that encased them.
Quebec was the hardest hit. Thirty thousand utility poles toppled and 1,000 metal transmission towers crumpled under the weight of the ice.
At the peak of the five-day storm, 3.5 million Quebecers — roughly half the population — were left in the cold and dark, in some cases, for weeks.
At least 35 Canadians were killed as a result of the storm, according to Public Safety Canada's disaster database — of carbon monoxide poisoning, trauma, fire and hypothermia.
Hydro bolsters system
For the last 15 years, Marie-Ève Grenier has worked as a planning engineer at Hydro-Québec. She said one of the lessons the utility learned from the ice storm is that the network will never be fully immune from a severe storm.
But Hydro-Québec has invested at least $2 billion since 1998 to fortify its network.
"We're confident that with the new standards and all the money that was invested in the system, the impact of another tragedy like we had in 1998 would be minimized. The service would be restored more quickly," she said.
In his report on the storm, engineer Roger Nicolet urged Hydro-Québec to bury its power lines.
Hydro concluded the cost of doing that would be $80 billion, too exorbitant to carry out. Instead, they opted to reinforce the overhead system.
One big change that was implemented was the introduction of what Hydro calls redundant sources of power supply in case of a transmission line failure.
It created a system whereby power is delivered using more than one path, so that if one line goes down, power can be supplied to customers using a different one.
It also reinforced and installed more of what the utility calls anti-cascading towers, meant to prevent the domino effect that saw ice-laden power lines bring down one tower, which toppled the next, and so on.
The 300 new towers are stronger and have been placed between two towers throughout the Montreal and Montérégie regions. They help cut down restoration times because when fewer lines fall, fewer have to be repaired.
The mechanical strength of the transmission lines themselves was also bolstered. The lines can now withstand higher ice loads because of improved engineering design standards incorporated into all new projects.
Hydro also developed a de-icing system that runs from the Lévis, Que., substation and can melt ice on 380 kilometres of transmission lines, Grenier said.
Will climate change lead to more freezing rain?
Christopher McCray, a PhD candidate in McGill University's department of oceanic and atmospheric sciences, studies the conditions that lead to ice storms over North America.
He says the area affected by the 1998 ice storm — southeastern Canada and northeastern U.S. — receives the most freezing rain of any area on the continent, for 20 to 30 hours every year.
The Montreal area gets up to four freezing rain events that last more than six hours, which is the threshold to be considered a significant event, McCray explained.
But similar kinds of weather patterns have occurred before and will occur again — for example, the system that led to Toronto's 2013 ice storm was similar, but it moved a bit faster so the impact wasn't as bad.
McCray said the question of how freezing rain trends will change due to climate change is an active area of research, but there are no clear answers yet.
However, when the atmosphere is warmer, the air can hold more moisture. A storm in a warmer climate may produce more precipitation, which we have been seeing with extreme rain and flooding events.
Could that apply to freezing rain events as well? Theoretically, McCray said. But we still can't pinpoint which areas could see more freezing rain.
"Meteorologically speaking, there's nothing that will prevent another 1998 type of ice storm from happening in the future. The main difference would be in terms of impact.… The impact would likely be very different," he said.
With files from Antoni Nerestant