In Mozambique almost 350,000 people are at risk. In neighbouring Malawi nearly a million people have been affected and 80,000 forced from their homes.
The UN has said the storm – named Cyclone Idai – may be “the worst ever disaster to strike the southern hemisphere”.
Mozambique has suffered massive damage to its roads and buildings, and declared three days of mourning for its dead.
“Rescue crews are still struggling to reach victims, while aid groups say many survivors are trapped in remote areas, surrounded by wrecked roads and submerged villages,” says one report.
Video is eight years old
The human tragedy hasn’t stopped false news about Cyclone Idai making its way onto Facebook.
A video posted on a South African Facebook page on 19 March 2019, titled “MUST WATCH”, claims to show “flood in Mozambique”.
The video has been shared nearly 450 times so far. But the footage actually shows waves from the 2011 tsunami in Japan devastating the port city of Miyako.
This is the original footage:
Plenty of other videos show the same event from different angles.
Nearly 16,000 people died as a result of the earthquake and tsunami that hit Japan in 2011. Some 2,500 people are still reported as missing.
The death toll from Cyclone Idai is yet to be calculated.
For publishers: what to do if your post is rated false
A fact-checker has rated your Facebook or Instagram post as “false”. What should you do? First, don't delete!
Click on our guide for the steps you should follow.
Africa Check teams up with Facebook
Africa Check is a partner in Facebook’s third-party fact-checking programme to help stop the spread of false information on social media.
The content we rate as “false” will be downgraded on Facebook and Instagram. This means fewer people will see it.
You can also help identify false information on Facebook. This guide explains how.