UPDATE

Power coming on in 'dribs and drabs' but could take a day or two

Just under 100,000 homes are without power as of Saturday afternoon in the Ottawa area and it could be days before it's restored to all customers.

'Crisis won't end' until workers deal with losing a major transformer station, says Hydro boss

The downed Hydro One-owned Merivale substation in suburban Ottawa. This transformer needs repairs before power can be restored to much of the city. (Leah Hansen/CBC News)

Just under 100,000 homes are without power as of Saturday afternoon in the Ottawa area and it could be days before it's restored to all customers.

That's a big improvement from Saturday morning, when 150,000 homes were powerless. Still, it could be a day or more before everyone is out of the dark.

"This is a multi-day outage," said Bryce Conrad, the president and CEO of Hydro Ottawa. "This is not a, go out for dinner, come home, your power will be on. This is going to take time."

The tornado that touched down at Hunt Club and Greenbank on Friday afternoon — one of a pair that struck the region — severely damaged the nearby Merivale Transformer Station, one of the two major funnels of power into the city. 

"It was devastated," said Conrad. "The roof blew off. It's just terrible. That accounts for a huge percentage of the power that comes into Ottawa."

Power will 'start to trickle back on'

The central power grid is run by the province, which is then distributed through a network down to individual communities. 

Hydro Ottawa, the city's local power distributor, relies on the transmission corridor operated by the province's Hydro One. The power in that corridor gets transmitted to Hydro Ottawa through two major Hydro One transformation stations — the Merivale transformer in the south end, and the Hawthorne Transformer Station near Walkley Road and Highway 417.

I'm more optimistic now than I was this morning.- Bryce Conrad, president and CEO of Hydro Ottawa 

The Hawthorne station is fine, which is why there's power on the east side of the city. But the damage to the Merivale station is accounting for at least 60 per cent of the outages.

The rest of the outages are due to the 80 hydro poles that are down, or other physical damage to infrastructure.

Conrad said that as the poles go back up, and both Hydro One and Hydro Ottawa rejig their systems to re-routed from power other sources, "the power will slowly but surely start to trickle back on" in what he referred to as "dribs and drabs."

And that's what's been happening across the city. A few neighbourhoods in Barrhaven, for example, now have power but large swaths of the area remain the dark.

West and south could be without power the longest

"I'm more optimistic now than I was this morning," said Conrad.

Still, the customers most directly affected by the Merivale station devastation are in the south and west parts of the city, and could be the people most facing a number of days without power — perhaps as late as Monday or Tuesday, according to  Hydro Ontario official.

"But because it's a series of cascading failures, it could be other parts," said Conrad. "I don't want to say, 'If you're in Westboro your power will be back on tonight.' I just don't know."

There are also local Hydro One customers without power in eastern Ontario who are also facing multiple days without power.