The Edmonton Tornado, 25 years later, still has the power to evoke memories and images of the violent destruction that earned it the name Black Friday.
The tornado struck July 31, 1987, killing 27 people and leaving hundreds of others injured and homeless.
One of the worst natural disasters in Alberta's history, the tornado changed the lives of those who survived its awful power.
"I discovered a few things during the tornado," John Marzolf told CBC News. "One of them was that I was no where near as brave as I thought I was, and that your life can change in a flash."
Marzolf was working for Computalog Gearhart Ltd. then located at 19th Street and 84th Avenue.
He recalls the heat, the humidity and the calmness of the afternoon when his colleagues spotted the funnel cloud.
"A bunch of us gathered at the wash bay door to watch the tornado approach, none of us thinking it might be a good idea to clear the area.
"As it came closer we could see the damage it was doing and the flashes as it ripped transformers from the poles as it moved northward along 34th Street."
'We all scattered'
Marzolf estimates the tornado was still 400 metres away when the air was sucked out of the bay, collapsing the cinder block wall behind him.
"We all scattered looking for a safe place. Some made better choices than others. I held on to an A-frame crane that was about as stable as Maggie Trudeau, and remember the roof moving up and down about three feet," he said.
"It lasted about 30-40 seconds and then everything settled down.
"Only one fellow was hurt at our building, when one of the bay doors blew in, but 300 metres to the west the damage was unbelievable."
A nearby railroad change-out station was completely destroyed, as were many other building along 84th Avenue, he said.
"Most of us then helped the firemen and police search the area and help people to ambulances," Marzolf said.
The tragedy did not end there for Marzolf and his coworkers.
One week after the tornado, he and a colleague were cleaning up the aftermath with a walk-behind sweeper.
As his friend walked backwards into the street to make another pass, he was struck by a car, said Marzolf.
'Everyone was in shock'
For the young, the tragedy of the day was hard to comprehend.
Adam Cavanaugh was an eight year old living in Mill Woods - the first Edmonton neighbourhood to be hit.
"The most emotional story I remember is when school resumed after this tragedy.
"Everyone was in shock, but kids that are seven or eight years old can't completely comprehend the damage," he said.
"Our teacher decided to have a discussion about what had happened and one girl, Tina, broke down completely - crying and screaming.
"We found out later that the roof had been ripped off of her house while they were taking shelter - her house was basically destroyed."
The tornado was building power as it sped northward, with windspeed eventually topping out at more than 400 kilometres per hour as it crashed into the Clareview neighbourhoods and Evergreen Mobile Home Park.
'I will never forget that terrible day'
Michelle Lovell was 10 years old, living in Clareview at the time.
"When it began to hail, my stepmother sent us out to pick hailstones, not realizing the danger," she said. "Dad brought that to an end quickly."
The tornado touched down blocks just a few blocks away, Lovell recalled.
"I remember when they gave the order on TV to take cover, crouching in Dad's pantry in tears with my rosary, saying 'Hail Mary' for what seemed like hours on end."
"I will never forget that horrible day, or the overwhelming outpouring of support for Edmontonians that came in from world-wide in the days and weeks to come.
"For all of the devastation that Edmonton suffered on Black Friday, I am fortunate to have learned two very important life lessons: how to take cover in a storm and that our relationships with people, even those we do not 'know,' is truly what is important in life."