Hunga Tonga might be Cape wet blanket

Cape Town is doing a very good sodden puppy impression – and Hunga Tonga could be behind it all.

We’ve lost count of the number of race meetings lost to rain and soggy ground in Western Cape over the past two months, but it must be about 10.

On Monday, Cape Racing announced that the meeting scheduled for Hollywoodbets Durbanville on Wednesday 28 August would move to Saturday 31 August at the same venue. The meeting originally down for the 31st shifts to Tuesday 3 September – also at Durbanville.

All the disruption is bad for racing and the natural reaction is to look for someone or something to blame.

Hunga Tonga

Climate change has of course been charged and convicted in the court of public opinion. As has the El Niño effect. Or is it La Niña, this time? But new research has put Hunga Tonga high on the list of suspects.

This is no rain-dancing sangoma. It’s a volcano on the other side of the world, which some might recall made minor headlines in January 2022 when it erupted.

It should have made much bigger headlines because it was a very unusual event with some major consequences.

When Hunga Tonga-Hunga Ha’apai erupted in the South Pacific Ocean kingdom of Tonga, it was said to be the largest volcanic event of the 21st century and the biggest submarine one anyone could remember.

It triggered a tsunami across the Pacific basin, drowned a few people, and sent sound waves around the globe several times.

Scientists reckon this volcano was responsible for the much-enlarged hole in the ozone layer in 2023. And a new study published in the Journal of Climate suggests it is bringing heavier-than-usual rain to parts of the world in 2024.

The most unusual aspect of Hunga Tonga was that it was an underwater volcano, belching out more water vapour than smoke and carbon dioxide.

Colder and wetter winters

It sent 100-150 million tonnes of water – or 60,000 Olympic swimming pools – spouting high into the sky. Or, rather, into the stratosphere, a layer of the atmosphere 15-40kms above Earth’s surface.

All this lofty moisture seems to change the way waves travel through the atmosphere, say scientists quoted in a recent article in The Conversation. Atmospheric waves are responsible for highs and lows, which directly influence weather.

To cut a long scientific story short, the broad prediction is for colder and wetter southern hemisphere winters until about 2029.

For the record, 30-year average rainfall for Oranjezicht in Cape Town in July is 128mm, but this year 317.6mm was recorded. At Kenilworth racecourse itself, some instruments measured up to 600mm for the month.

“This notable total not only exceeded the historical average, but it is also the highest monthly rainfall recorded for July since comprehensive records began in 1960,” said the South African Weather Service.