Analysis of the recent destructive weather event in Montana, north of Pretoria, has been confirmed as a landspout and not a tornado.
This as the South African Weather Service (SAWS) conducted a thorough analysis of the destructive weather event that took place on Tuesday, 18 February.
“Following the analysis, which included visits to the site of the event and a close study of high-resolution satellite images of the event, among other things, the SAWS has concluded that the event was, in fact, a landspout as opposed to a tornado,” the weather service said on Friday.
In its statement it explained that a landspout develops over land and is generally smaller and weaker. A tornado, on the other hand, is a violent rotating column of air that extends from a thunderstorm and measures less than a few hundred meters in diameter although some are larger than 1 km.
“Tornadoes and landspouts are two small-sized events that the SAWS is working tirelessly to nowcast for the benefit of the public. Unlike with other weather conditions, signs of the potential development of a tornado are very evasive, particularly for landspouts,” it explained.
However, there has been an instance where the SAWS issued a tornado warning before its formation (on Saturday, 30 December 2017) albeit four minutes before it struck.
“Both tornadoes and landspouts have a similar appearance, but their development mechanisms and strengths differ. It is for this reason that the SAWS conducted a thorough analysis across Montana after which it was concluded that the event was a landspout.”
The landspout developed shortly before 5pm local time and affected a short stretch to the busy Sefako Makgato Drive.
From there, it uprooted trees and remained on the one side of the main road. Eyewitnesses estimated that this landspout took less than five minutes before lifting and disappearing.
The trace of its weakened phase was noted towards Zambezi where only tree branches were broken off with a zigzagging motion to the right side and back to the left of the main road.
Here, carport awnings and more roof sheeting were broken, twisted and lofted into the air.
“It is miraculous that, to date, no reports of deaths or injuries have been received.
“The landspout was rated as an EF0 according to the Enhanced Fujita (EF) scale for tornado intensity, which is in use internationally. An EF0 event is generally associated with light or minor damage and corresponds to estimated wind speeds of the order of 90 to 130 kmh,” SAWS said.
At the time of the incident, the SAWS had an Orange Level 5 Impact-Based weather warning in place over Gauteng and adjacent provinces for disruptive rainfall and/or localised flooding.
Action to be taken when either a landspout or tornado strike:
• Where possible, quickly get out of the zone to which two thunderclouds are moving. Within such zones, it is almost certain that the wind will be strong and potentially damaging with injurious debris. Community members at the sudden start of a tornado or landspout may be caught by surprise, but each next minute should be used effectively.
• Do not use a tree as shelter when it is positioned in the path of a tornado or landspout.
• Loud sounds associated with tornadic impacts should quickly be used to scan the direction of clouds some distance away from the tornado / landspout. Thereafter, move out of the path of this event before moving opposite the main direction of clouds. Then find refuge.
• When indoors in a formal house, remain in a small room such the bathroom.
• To minimise impact for the shack dwellers, use the inside of small-sized furniture such as a sided wardrobe.
The SAWS said such action validates the saying “save one life, safe the world”.
Situational awareness creates a smooth and continuous defence against potential weather hazards, and it forms part and parcel of the Early Warning for All (EW4All) initiative.
The EW4All was introduced by the United Nations to ensure that everyone on earth is protected from hazardous weather, water, or climate events through lifesaving Early Warning Systems by the end of 2027.
“The public can be rest assured that SAWS, as mandated by the SAWS Act (Act 8 of 2001), will continue to monitor and assess developing weather systems and endeavour to issue weather-related Impact Based Early Warnings in a timely manner,” it said.
Such early warnings are routinely disseminated via mainstream news platforms such as radio, television, printed media as well as the SAWS website www.weathersa.co.za .
Additionally, pertinent information regarding on-the-ground impacts and significant expected weather events are posted on major social media platforms such as X (previously Twitter) @SAWeatherServic, Facebook (South African Weather Service) as well as YouTube. – SAnews.gov.za
