Thick fog enveloped the apron of O.R. Tambo International Airport on Monday morning, making the tail of an aircraft barely visible through the mist. Passengers expecting to land at O.R. Tambo were redirected to Lanseria the same day because the dense fog made landing too risky.
A representative from Airports Company South Africa (Acsa), Ofentse Dijoe, confirmed the reroutings to IOL. Due to low visibility, air traffic controllers restricted airport operations to one runway, which led to delays and diversions. In a notification for passengers, Acsa warned travelers about possible disruptions.
The notification stated: 'Please note that the airport is currently experiencing low visibility due to adverse weather conditions.' It further clarified: 'As a result, some arriving flights may be diverted to alternative airports, and delays to arriving and departing flights are possible.' Passengers were advised to check the current flight status with their airlines before traveling to the airport, adding apologies for the inconvenience and emphasizing that safety remains the highest priority.
Kirby Gordon, Marketing Director for FlySafair, informed IOL that the low-cost airline faced two diversions and one delay by mid-morning. Gordon confirmed the presence of very thick fog in the area and noted that ATNS temporarily reduced operations to one runway for safety, causing delays and diversions. He added that there were two diversions and one delay so far, which is not yet a critical situation. Meanwhile, SA Weather Service forecasts that the fog should dissipate by 9:30 AM.
Aviation meteorological data for Monday showed that visibility in the fog dropped to 150 meters, while the fog reduced visibility to 4000 meters during the morning. SA Weather Service had previously forecast morning frosts in some parts of Gauteng, with moderately cloudy and cool conditions expected, as well as isolated showers and thunderstorms. Fog and smog are common phenomena over Highveld during winter mornings.
This phenomenon, known as radiation fog, forms on cold, clear, and windless nights when the ground loses heat, and the air directly above it cools to the point where moisture condenses into a thick blanket of suspended water droplets. Typically, this fog dissipates within a few hours after sunrise as the sun warms the ground. Poor visibility reduces the speed at which aircraft can safely land and take off, forcing controllers to either increase intervals between flights or direct them to other airports.
The main alternative to O.R. Tambo was Lanseria International Airport, a private facility located approximately 45 kilometers northwest of Johannesburg. Previously, fog had caused serious disruptions at O.R. Tambo: in 2021, poor visibility due to early morning fog led to the diversion of 24 flights to other local, coastal, and regional airports.
