'Ice Saints' bring rain and make dry rivers flow

Conditions had actually been almost summer-like and warm. But then, an icy wind suddenly blew in again. And with the cold snap came the clouds. It rained for days in southern Namibia. Over the weekend, the Tsauchab, Tsondab, and other riviere (ephemeral rivers) were flowing across their full width.

Farmers between the Kalahari and the Namib Desert reported rainfall of 10 to 50 mm. At BüllsPort Lodge & Farm on the eastern edge of the Naukluft Mountains, 40 mm of rain fell on Friday alone. Consequently, the Tsondab River flowed heavily. The ford on the C19 road from Solitaire towards Sossusvlei, west of the Naukluft, was impassable for hours.

The Tsauchab River, which originates south of BüllsPort, was also flowing across its entire width. However, it seems doubtful whether its waters will reach Sossusvlei, as speculated on social media. Photos, video clips, and information regarding the rainfall can be found in the 'Reën In Namibia' Facebook group.

The Fish River contributed to the Hardap Dam near Mariental and the Neckartal Dam west of Keetmanshoop. However, the Fish River Canyon, located about 100 km south of the Neckartal Dam, is unlikely to face a flood surge. There was certainly no talk of closing the Fish River Canyon Trail.

After the flood wave... For hours, the Tsondab rivier (dry river) also flowed so strongly that several fords were impassable by vehicle. Photo: Facebook post by Gondwana Collection Namibia.

Rain also fell in Windhoek, though amounts were less than 10 millimeters. The icy wind prompted many residents to dig long trousers or dresses and sweaters or jackets out of their wardrobes once again. Meteorologists are forecasting another cold front for the final weekend of September (see Facebook Reel).

Last good rain before a super 'El Niño' drought?

German speaking Namibians, in particular, refer to the final cold fronts of spring, when winter makes a brief comeback, as the 'Ice Saints' ('Eisheilige'). The term originates in Europe, where traditional agricultural lore suggests a final cold snap can be expected in mid-May.

In Namibia, however, this phenomenon is caused by a 'cut-off low', an upper-level low-pressure system detached from the main flow of the westerlies. This weather pattern is typical of the transition from winter to spring, occurring between mid- and late September. If a low-pressure system moves in from the south, rainfall may occur.

However, this rain is still classified as winter rainfall. Namibia's main rainy season, characterised by cloud formation from moist air arriving from the northeast and by thunderstorms, usually lasts from October to April. That said, the term 'rainy season' is misleading. In reality, rain is simply more likely during this period than during the dry season.

Forecasts for the upcoming 'rainy season' are tempering expectations. Meteorologists are warning of a super 'El Niño' event. Namibia could consequently face a period of drought (see the report "Is Namibia prepared for the coming super El Niño drought?" on ConservationNamibia.com).

Late winter rain in southern Namibia has set the riviere (ephemeral rivers) flowing, such as the Tsauchab, shown here, which ends at Sossusvlei.  Photo: Screenshot from a video clip widely shared on WhatsApp.