Rare cut-off low brings snow, icy conditions to Johannesburg and parts of South Africa

A rare cut-off low weather system has delivered icy rain, bitter cold and flurries of snow to Johannesburg and parts of South Africa, with forecasters and climatologists warning the wintry conditions could continue through the day.

What forecasters reported

South Africa’s weather forecaster warned that heavy snowfall is likely in parts of the Eastern Cape and that freezing temperatures, icy roads and hazardous travel conditions are expected to continue in affected areas.

How the system formed

Climatologist Professor Jennifer Fitchett of Wits University’s School of Geography, Archaeology and Environmental Studies said the system developed from a cold front that moved across the Cape and South Coast.

She described a cut-off low as a section of cold, low-pressure air that separated from the main weather system, became stationary and positioned over the interior.

“Unlike cold fronts that move through relatively quickly, a cut-off low can remain over an area for longer, bringing very cold and moisture-rich conditions. These systems are responsible for much of South Africa’s snowfall and for the snow that occasionally falls in Johannesburg,”

Expected conditions in Johannesburg

Prof Fitchett said the small flurries seen in the morning are likely to continue through the day and that there is a possibility of greater amounts of snow later in the evening.

“The small flurries that we’ve seen this morning are likely to continue through the day, and we may even see greater amounts of snow towards the evening.”

She added that while snow in Johannesburg is uncommon, it is not unusual because the city’s high altitude can allow temperatures to fall low enough for snow when the right weather system is present.

“The city’s high altitude means temperatures can occasionally become cold enough for snow when the right weather system is present.”

On links to climate change

Prof Fitchett cautioned against attributing this single snowfall event directly to climate change without detailed research, noting that scientists need long-term records to determine changes in frequency.

“Scientists generally need long-term records to determine whether events such as snowfall are becoming more frequent, while studies that establish whether climate change contributed to a specific extreme weather event can take considerable time.

At this point in time, we wouldn’t say that it’s happening more frequently. We might wait another two years for another snow. We might wait another 20 years,”

She also said scientists are seeing greater unpredictability in weather and climate events as climate change intensifies.

Practical implications

The combination of freezing temperatures, icy roads and possible heavier snow later in the day points to continued hazardous travel in affected areas. Residents in impacted regions should be aware of the warnings issued by the weather service.