TORONTO -- Beirut residents frantically attempted to get in touch with missing friends and loved ones Wednesday as the extent of the previous day's deadly explosion left the Lebanese capital reeling.

"Entire neighbourhoods have been reduced to rubble. Cars have been overturned. People lost their homes, their livelihoods," Aya Majzoub, a Lebanon researcher with Human Rights Watch, told CTV News Channel on Wednesday.

"The level of devastation is just – I can't put it into words. It's a humanitarian catastrophe."

The death toll continued to climb on Wednesday, reaching at least 100. Another 4,000 people were injured.

When the blast occurred, Majzoub was in her apartment. She said she felt a tremor that she thought was an earthquake, and noticed that her building was shaking.

"A few seconds after that, there was an incredibly loud blast. I heard glass shatter and screams of people from my building who had been injured," she said.

Walking down to the street – four kilometres from the epicentre of the explosion – Majzoub discovered that "almost every single building had been damaged."

Many Beirut residents have similar accounts. Ahmed Yassine was in his car, heading home from work, at the moment of the explosion. The senior producer at Alaraby TV, said he saw “a cloud of smoke” cover everything.

“My car jumped, I saw people flying,” he told CTV News Channel on Tuesday. “Stores, apartments, houses, everything fell down. People were screaming, running.”

Video footage posted to social media shows the shocking moment that the second explosion hit, mere minutes after the first.

Towering plumes of smoke were already climbing into the sky from the port when a second, red cloud shot up — immediately surrounded by a dome of white as the shockwave of the explosion thrust outwards into the city, blowing out windows for kilometres.

Journalist Sunniva Rose saw that mushroom-shaped cloud rise as she drove into the city to get as close as she could. Speaking to CTV News Channel on Tuesday, she described the atmosphere near the epicentre as "like a war zone.

"I saw body bags on the street. I saw so many people who are injured and walking around looking completely lost," she said.

"Even the ambulances couldn't really drive through the streets, because it was such pandemonium."

The blast could be heard and felt in Cyprus, more than 200 kilometres away.

Yassine said he was around four kilometres from the radius of the explosion when it occurred, but luckily, escaped harm.

What he could not escape was the horror of the situation.

“Glass, stone, buildings cracking. It was really terrifying,” he said.

Nada Hamza, another resident of the city, was even closer to the blast when it reverberated through the city.

“I was in the street just behind the port of Beirut,” she told CTV News Channel over the phone on Tuesday, estimating that she was within one kilometre of the explosion.

Like Yassine and Rose, she had been in her car when she heard the first warning sounds of the devastation that was to come.

At first, she thought she heard “bombs,” she said. She rolled down her window to ask others in the street what was happening, thinking at first that it might be protesters having a “fight or clash with the government.”

Then the sound shifted. It sounded like airplanes, she said -- making those around her fear it could be an attack from Israel. There have been rising tensions recently between Lebanon and Israel.

“And then we saw the smoke, we saw the fire, we heard the explosion,” she said.

Unsure if the city was under attack or not, Hamza initially abandoned her vehicle.

“I left my car in the middle of the street. I ran away to hide in a building,” she said. “I was totally confused and scared.

“The street was almost destroyed.”

The explosion is believed to have been caused by a fire reaching a large quantity of ammonium nitrate that had been stored at Beirut's port for several years. It is not clear what caused the fire, although there is no evidence that it was a deliberate attack. Many in Lebanon are blaming the blast on a failure of government.

Yassine said that although the city has weathered many crises, this explosion feels different.

“We faced wars … we survived many explosions. But this one is totally new. It’s another kind of explosion.”

It’s a huge blow to a city and country ravaged by a financial crisis and the COVID-19 pandemic.

“Our hospitals are not that ready to hold too much people,” Hamza pointed out. “Because of COVID-19, our medical institutions in Lebanon and establishments are not well equipped.”

Already, she’s seen numerous acts of kindness among survivors, but acknowledged that the true toll of this tragedy is something they aren’t able to wrap their heads around yet.

“Lebanese people now are trying to help each other,” she said. “We’re trying to open doors for people who lost their places, our houses. We try as much as we can to help each other, but we’re still under the shock. We don’t know what’s going on.”

As the city moves forward and attempts to recover from this tragedy, Majzoub said she wants concrete answers to replace the "speculation" currently engulfing the city.

"Why did nobody act? Why was such a huge quantity of explosive material allowed to remain in a storage facility surrounded by citizens for so long?" she said.

Yassine hopes there will be justice.

“Someone must pay for that,” he said. “Especially the people who are responsible for storing such materials in a place where there is many people around.

“It’s a place where poor people live.”

Yassine pointed out that the explosion destroyed many resources stored at or near the port that the city needed in this “economical crisis,” such as a large supply of wheat.

Without the city’s port, “how are we able to survive?”

With files from The Associated Press