As Ottawa marks the 10-year anniversary of one of the biggest blackouts in history, a local hydro official says lessons learned mean a repeat is unlikely.

At 4:13 p.m. on Aug. 14, 2003, an untrimmed tree in northern Ohio hit a transmission line, triggering a domino effect through the North America's northeast.

Hydro Ottawa’s chief operating officer Norm Fraser said he was called in from vacation and ended up working four days straight.

"People thought 'well maybe terrorism, maybe an airplane,'" he said while holding a black "Ottawa Hydro Blackout 2003 – I Was Here" t-shirt.

"Turns out to be a tree," he said.

Do you have any stories of the blackout in Ottawa that you'd like to share? Tweet us @CBCOttawa or send an email to cbcnewsottawa@cbc.ca

He said a joint Canadian-American task force made 43 recommendations designed to avoid another blackout of that size – one that had 50 million people in the dark across eight northern states and Ontario.

"The reliability standards for the international electrical system prior to this was voluntary. Now they are mandatory and they're enforced, that's a huge change," he said.

Street parties popped up as food spoiled

Fraser said power was restored to most of Ottawa after two days without electricity.

The shutdown cancelled flights, darkened traffic lights and spoiled food for millions, causing 370 calls for fires and 23 looting cases in Ottawa alone.

"We ended up throwing out a lot of food, food we may have been able to serve but if it's questionable you don't want to take a chance," said Bob Jones of the Mayflower Pub.

Businesses and homes alike lost food when their refrigerators stopped working. (CBC)

He said they took a financial hit from the lost business, but still managed to have a good time.

"There was a lot of camaraderie. There were people across the street who brought out some lawn chairs and a table. They had recorded music going on – it was a street party.

Charity run cancelled so generators could go elsewhere

Runners were scheduled to participate in a fundraising race for the Royal Ottawa Mental Health Centre the day after the blackout, according to then-head Tim Kluke.

He said the run was cancelled when organizers realized their generators could be put to better use elsewhere.

"A thousand people raising money, which is great, but should they be at nursing homes, hospitals?" he said.

"(It was a) difficult decision when you spend a whole year organizing an event … but it was the right decision."

Kluke said they still managed to raise almost $200,000.