A teenaged boy is in hospital in critical condition after being struck by lightning during Friday evening's thunderstorms.

Ottawa paramedics said the 18-year-old was biking through Vincent Massey Park with an 18-year-old girl when the storm hit just after 7 p.m.

The pair stopped under a tree to put on their rain gear and both the tree and teen were hit by lightning.

When paramedics arrived they said the boy was unconscious and in cardiac arrest.

They immediately started working to get his heart going again, and he was reported to be in critical condition when he arrived in hospital.

The girl was also taken to hospital with numbness in her arms, but paramedics said they weren't sure if she was also hit by lightning.

Ottawa fire crews were kept busy with downed trees and wires when the line of storms blew through the city around 6:40 p.m.

Lightning struck a clothesline at 27 Smirle Avenue, west of downtown Ottawa, around 6:44 p.m.

The electricity moved through the line and onto the aluminum-framed window of the house, but there was no fire when crews came to check.

A 60 foot by 25 foot section of roofing blew off an apartment building at 350 Mayfield Street in east Ottawa just before 7 p.m., causing water damage to five apartments.

Three people have been displaced as a result, with the Salvation Army and Red Cross helping them.

"If they need accommodation that's the Red Cross' area," said Major Neil Evenden of the Salvation Army. "If they need furniture, clothing or any other support the Salvation Army steps in."

Neighbours said there was a near miss in the west end when a tree blew over, luckily missing anything valuable.

"We were in the living room and the rains came up very heavy, within moments the tree was laying in the street," said Owen Phillips, who added he was glad his basketball net was spared.

Adam Yang wasn't so lucky, as his business' delivery van was heavily damaged.

"It looks like damage is pretty large, at least in the windshield and the front hood," said Adam Yang. "I don't know what I'm supposed to do, I had a couple of movings arranged in the next few days, looks like they'll have to be cancelled."

Damage could have been much worse if a tornado had touched down in the region, as areas west and north of Ottawa were under a tornado warning for about 90 minutes Friday evening.

With a report from CTV Ottawa's Katie Griffin