Rescue teams began a third day searching for missing people Thursday after floods devastated parts of South Africa's rural Eastern Cape province and left at least 49 dead.

Authorities said they expected the death toll to rise.

The missing included four high school students who were swept away when their bus was caught up in the floods near a river on Tuesday. Six students on the bus were confirmed dead, while three were rescued after clinging onto trees and calling out for help, according to the provincial government.

The floods hit the province early Tuesday after an extreme cold front brought heavy rain, strong winds and snow to parts of eastern and southern South Africa. Forecasters had warned about the damaging weather last week.

Eastern Cape provincial government officials said they believed people were still missing but did not give an exact number. They were working with families to find out who was still unaccounted for, they said.

On Wednesday, rescue teams brought bodies out of the water in blue body bags, while witnesses said many people had taken refuge on the top of buildings or in trees.

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The floods centered on the town of Mthatha and its surrounding district, which is around 430 kilometers (267 miles) south of the east coast city of Durban.

Officials said at least 58 schools and 20 hospitals were damaged, while hundreds of families were left homeless after their houses were submerged under water or washed away by the floods. Critical infrastructure including roads and bridges has been badly damaged, Eastern Cape Premier Oscar Mabuyane said.

He said it was one of the worst weather-related disasters his province had experienced.

South African President Cyril Ramaphosa announced he had activated the National Disaster Management Center to help local authorities in the Eastern Cape, while national officials were expected to visit the province on Thursday.