Weather tracker: rain batters Argentina and DRC as fog shrouds India and Pakistan

During the Christmas period, parts of South America experienced intense showers and thunderstorms, resulting in substantial rainfall in various regions. On Monday, more than 100mm of rain fell in the Catamarca province in Argentina, which led to flash floods. A sudden surge in river water levels then caused the collapse of a pedestrian bridge, which was the only link between the towns of Rincón and Pomán. While many other roads in the region were damaged and houses were flooded, no casualties were reported.

The unique topography of Catamarca aided the formation of a near-stationary convective shower over Pomán, unleashing several hours of torrential rain and causing catastrophic flooding.

The Democratic Republic of the Congo has also been affected by severe rainfall over the past week. On Tuesday night, heavy rains hit the eastern region, resulting in flooding, mudslides and landslides. So far, 40 bodies have been recovered in Bukavu and the surrounding areas. This comes less than a week after 20 people were killed in similar conditions in the Mwenga territory of South Kivu.

North-west India has been experiencing poor visibility over the past few days. Delhi has been particularly badly affected, with visibility plummeting to close to zero metres between 8am and 10am on Wednesday. Parts of Pakistan were also badly affected by the dense fog on Wednesday.

Widespread disruption to road, rail and air networks was reported by both countries, alongside several severe road incidents. Fog forms when air is cooled to the dew point – the temperature at which water vapour condenses – essentially forming a cloud at surface level.

Temperatures across Pakistan and north-west India have been lower than usual, helping fog to develop. When fog is combined with pollutants, smog develops. This has widely been seen across north-west India, with air quality being classified as very poor by the India Meteorological Department, which could pose serious health risks.

Northern Turkey also experienced dense fog on Thursday. This led to a serious road crash involving seven vehicles, including three buses, killing 10 people and injuring 57 others.