“Shipping has been suspended until further notice as a result of environmental damage caused by the adverse weather, and vessels on berth are on standby,” spokeswoman Ayanda Shezi said in statement. “There have been no major incidents reported at the terminals thus far.”

Two key highways linking the port of Durban to the commercial hub of Johannesburg and its eastern seaboard were shut on Tuesday because of the flooding.

The so-called N3 highway that connects Johannesburg to Durban was closed to southbound traffic because of debris on the road, KwaZulu-Natal’s Transport Department said on Twitter. Some bridges on the N2, the main highway along the nation’s Indian Ocean coastline, have been washed away, Parboo Sewpersad, a spokesman for eThekwini Metropolitan police, said on Durban-based East Coast Radio.

At least 20 people may have been killed because of the flooding, Johannesburg-based broadcaster eNCA reported. Local media reports showed videos and images of A.P. Moller-Maersk A/S-labeled shipping containers adrift in the water.

“The inclement weather conditions are expected to continue today” in areas around eThekwini municipality, which includes Durban, KwaZulu-Natal’s Cooperative Governance and Traditional Affairs department said in a statement. “This increases the risk of flooding getting worse in all these areas.”

South Africa’s largest exporter of thermal coal, Thungela Resources Ltd.’s operations have resumed after a “small interruption” on Monday, a spokeswoman said via email. Rival Exxaro Resources Ltd. said it hasn’t been affected.

South Africa is this year experiencing the La Nina weather phenomenon, which usually causes above normal rainfall in the country and its neighbors. In January, many parts of the nation experienced the heaviest rains since tracking by district began in 1921.