Flooding
Warning issued for localised flooding and thunderstorms in parts of Gauteng
Forecasters said the heavy rains could cause damage to buildings and other structures, especially in informal settlements.
Several structures and vehicles were damaged by violent storms in various parts of the province.
Provinces, including Gauteng and the Free State, are already battling extensive damage to roads and infrastructure due to the sustained downpours.
It is understood the children, two 10-year-olds and one nine-year-old, were found in the trench which had accumulated water due to heavy rains that lashed parts of Gauteng over the past 48 hours.
Typhoon Vamco packed winds of up to 155 kilometres (96 miles) per hour as it swept across Luzon after making landfall overnight, with authorities warning of landslides and potentially deadly storm surges along the coast.
The South African Weather Service said there was a 60% chance of heavy rain and thunderstorms in the province that are likely to continue into Thursday.
Forecaster Venetia Phakula said while today's thunderstorms were expected to be calm, they could lead to flooding, especially in low-lying areas.
Roads in the Johannesburg CBD, parts of Soweto and Roodepoort were left flooded when a thunderstorm moved through the province.
The weather service issued a level 2 alert for potential severe downpours earlier this week, with several parts of the province expected to be hit by some rough weather conditions.
The thunderstorm is expected to hit in the early afternoon and could last until about midnight.
Aid needs are likely to surpass 2019 levels, according to the UN's Office for the Coordination of Humanitarian Affairs.
We must face the fact that destructive rainfall is here to stay - and build homes that match that, writes Yonela Diko.
The latest cold snap made landfall late Sunday night, causing flooding across parts of the city.
The Zwelitsha informal settlement on a flood plain in Dunoon has been completely flooded.
The cold front is expected to tighten its grip on the province on Friday.
The SA Weather Service said that snowfall was expected in KZN, the Free State and the Eastern Cape as temperatures plunged across the country as well as in the mountains of neighbouring Lesotho.
There were heavy showers over the past few days and the SA Weather Service said there was a slight chance of rain on Tuesday.
The rains which began yesterday afternoon caused delays on the roads and stoked fears of prolonged disruption.
Heavy downpours caused flooding, road closures, and accidents, while parts of Alexandra, Soweto, and Centurion were hardest hit by the overnight rain.