The storm's sustained winds weakened to 75 kph after it moved inland, where it was expected to become a tropical depression by Thursday, before heading back into the Gulf of Mexico on Friday, where it could gather strength again.
Nisarga comes just two weeks after Cyclone Amphan tore through the Bay of Bengal on India’s east coast and battered West Bengal state, killing more than 100 people in India and neighbouring Bangladesh.
Bertha could unleash heavy rainfall and produce life-threatening flash flooding as it makes landfall along South Carolina coast, National Hurricane Center says.
Authorities have been struggling with the aftermath of Cyclone Amphan, while also dealing with the challenges of coronavirus outbreak.
Governor of Sheikh Othman district of Aden in southern Yemen is also among the dead from chikungunya fever which is a viral illness that is spread by the bites of infected mosquitoes.
It wasn't clear whether the combination of destroyed housing and social distancing requirements due to Covid-19 outbreak would lead to problems for tornado survivors, some of whom said they planned to stay with relatives.
Mississippi Emergency Management Agency director Greg Michel said one person killed was in Walthall County, two were killed in Lawrence County and three were killed in Jefferson Davis County.
The North African country has been battered by heavy rain and strong winds that began in the earlier hours of Thursday and continued on Friday.
Violent storms in recent days have dumped a month's worth of rain on some areas in a matter of hours, devastating the southern coast of Sao Paulo state and poor neighbourhoods on the outskirts of Rio de Janeiro.
The Pearl River rose to its third-highest point in recorded history after heavy rains last week filled the Ross Barnett Reservoir to capacity, forcing managers on Saturday to begin releasing water into the river just upstream from Jackson.
A 55-year-old woman was found dead after being swept away near the flood-prone town of Tenbury Wells in western England.
The new supercomputer, which will be managed by the country's Met Office, will be used to help more accurately predict storms, select the most suitable locations for flood defences and predict changes to the global climate.
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