Follow the latest updates on the Libyan floods
The storm wreaked havoc across eastern towns causing flash floods in many areas, including the city of Derna, where dams were destroyed and entire neighbourhoods washed away.
The death toll in Derna had risen to 5,300 by Wednesday morning, the Interior Ministry appointed by the country's parliament said.
Nearly 10,000 people are reported missing.
At least 600 people who died in floods in Derna were buried in mass graves, a resident told The National.
Dr Salem Abu Fanas, Dean of Dentistry College at Ajman University, found himself in a state of despair as he tried to reach his family in Libya.
“Most of my family lives safely in the city of Misurata in Libya,” he told The National.
But one of his brothers, and his daughters and their families, live in Al Bayda, where roads and buildings were damaged by the storm.
At least 50 people are reported dead in Al Bayda and its main hospital was flooded, forcing the evacuation of patients, according to a post shared by the hospital on Facebook.
“I immediately called him, but there was no way of reaching him,” Dr Salem said.
“So I called my brothers in Misurata, who confirmed he was safe.
“But the sadness and feelings of loss and uncertainty held me captive until I finally heard his voice.”
Dr Salem said his brother lost his entire brick factory, a lorry and a car as a result of the floods.
“Not only that but the security guard at the factory was washed away and is missing, believed to be dead,” Dr Salem said.
“This is not the first time Al Bayda witnessed such a storm.”
A similar storm struck the region around 60 years ago, but the city was barely populated back then, said Dr Salem.
“It's God's will in the end. However, one can't help but think if Libya was not divided between two rival governments, it wouldn't have been left with inadequate infrastructure,” he said.
“Had it been more stable, there would have been better preparations that could have helped minimise the losses in lives and property.”
Dr Matouk Zbaeda, a medical director at a hospital in Abu Dhabi who lost friends in the flood, agreed.
“Shock isn't even the word,” he told The National.
“Entire families have vanished in the blink of an eye. It is unimaginable and what's worse is that we don't even know the extent of it yet.
“It will be a lot worse and we expect total deaths to be much higher than what was reported,” he said.
Dr Zbaeda, from Tripoli, said he lost both friends and a classmate in the floods.
“They were at home when the floods hit. Then in a few minutes, the entire family was gone. Siblings, children, in-laws, parents and everyone in that area,” he said.
“What's hard is that there was no communication with them and then the videos started coming out and we couldn't contact them or call anyone to rush to their aid which was the first instinct.”
“I've been trying to find flights. Getting to Libya is difficult on a normal day. Imagine it now? No one is able to get in or out,” he said.
Dr Zbaeda's son, who is based in Britain, is also trying to gather aid and donations for the people in Libya.
“There are only around six million Libyans and now so many are gone. We still can't process what happened and the problem is that it is only getting worse,” he said.
“It will be weeks until we know the magnitude of it all.
“You hear of these things happening in other countries or see it in movies, but you would never imagine it happening to you, in your home country,” he said.