Dense fog diverts flights from OR Tambo to Lanseria as poor visibility causes delays

Passengers expecting to touch down at OR Tambo International Airport ended up at Lanseria on Monday morning after dense mist made landing too risky.

Airports Company South Africa (Acsa) spokesperson Ofentse Dijoe confirmed the diversions to IOL.

Air traffic controllers reduced the airport to a single runway because of poor visibility, causing delays and diversions.

In a passenger notice, Acsa warned travellers to expect disruptions.

“Please be advised that the airport is currently experiencing low visibility due to adverse weather conditions,” the notice read.

“As a result, some arriving flights may be diverted to alternate airports, and delays to arriving and departing flights are possible.

“Passengers are encouraged to check the latest flight status with their respective airlines before travelling to the airport.

“We apologise for any inconvenience and appreciate your patience and understanding as safety remains our highest priority.”

FlySafair chief marketing officer Kirby Gordon told IOL the low-cost carrier had been affected by two diversions and one delay by mid-morning.

“Yes, there is very dense mist over the area at the moment,” Gordon said.

“ATNS has reduced operations to a single runway for the time being in the interest of safety, which is resulting in some delays and diversions this morning.

“We’ve had two diversions and one delay so far, so not too terrible yet.

“The SA Weather Service is advising that it should lift by 9.30am.”

Aviation weather data for the airport on Monday showed visibility dropping to as low as 150m in fog, with mist reducing visibility to 4,000m through the morning.

The SA Weather Service had forecast morning frost in places over Gauteng, with otherwise partly cloudy and cool conditions, as well as isolated showers and thundershowers.

Mist and fog are common over the Highveld on winter mornings.

The phenomenon, known as radiation fog, forms on cold, clear and windless nights when the ground loses heat and the air just above it cools to the point where moisture condenses into a thick blanket of suspended water droplets.

It typically burns off within a few hours of sunrise as the sun warms the ground.

Poor visibility reduces the rate at which aircraft can safely land and take off, forcing controllers to space flights further apart or divert them to alternative airports.

Lanseria International Airport, a privately owned facility about 45km north-west of Johannesburg, served as the main alternative to OR Tambo.

Fog has caused major disruptions at OR Tambo before, with poor visibility from early morning fog diverting 24 flights to other local, coastal and regional airports on one occasion in 2021.

IOL