Another ice storm could happen. Is Hydro-Qubec ready?

Two decades after one of the worst natural disasters in Canadian history began, a climate scientist atMcGillUniversityis warning thatQuebecersaren't immune fromexperiencing anotherice storm like the one that crippled much of the provincein 1998.

ButHydro-Qubecreassuresclients that if a similar storm were tohit, 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 theboom and flash of light from exploding transformers, the crack of tree branches collapsing under the weight of the ice that encased them.

• PHOTOS |Looking back on the 1998 ice storm 20 years later

Quebec was the hardest hit. Thirty thousandutilitypoles toppled and 1,000 metal transmission towerscrumpled under the weight of the ice.

At the peak of the five-day storm, 3.5 millionQuebecers roughly half the population were left in the cold and dark, in some cases, for weeks.

At least 35Canadians were killedas a result of the storm, according to Public Safety Canada's disaster database of carbon monoxide poisoning, trauma, fire and hypothermia.

Hydro bolsterssystem

For the last 15 years,Marie-veGrenierhas worked as a planning engineer atHydro-Qubec. 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.

ButHydro-Qubechas 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.

• Ice storm lessons endure 10 years after disaster

In his report on the storm, engineer RogerNicoleturgedHydro-Qubecto bury its power lines.

Hydroconcludedthe cost of doing that would be$80 billion, too exorbitant to carry out. Instead, they opted to reinforce the overhead system.

"We had to reach a compromise between reliability and cost,"Greniersaid.

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 andinstalled more of what the utilitycalls 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.

"In 1998, we had over 40, 50 kilometres of transmission lines that fell.[With] the new anti-cascading system, the towers are placed every five kilometres, so we make sure the impact would be minimized,"Greniersaid.

The 300 new towers are stronger and have been placed between two towers throughout the Montreal andMontrgieregions. 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 linescan now withstand higher ice loads because of improvedengineering design standards incorporated intoall new projects.

Hydro also developed a de-icing system that runs from theLvis, Que., substation and can melt ice on 380 kilometres of transmission lines,Greniersaid.

Will climate change lead to more freezing rain?

Christopher McCray, a PhD candidate inMcGillUniversity's department ofoceanic and atmospheric sciences, studies the conditions that lead to ice storms over North America.

He says the area affected by the 1998 ice stormsoutheastern Canada and northeastern U.S.receivesthe 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, McCrayexplained.

The weather system during the 1998 ice storm was unique because it moved so slowly. High and low pressure systems coming from different directions blocked each other from moving, so the freezing rain just kept falling.

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.

• Fromthe archives: The Ice Storm of 1998

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.