Image: Modis - NASA (Click on image for larger view.)
This event is now something of the past. (hopefully) Thankfully it did not left a trail of destruction in it's wake. I will summarize a few "interesting facts" regarding this cut-off low system. I will not go into detail as this blog contains most if not all of the information.
1. Cut-off low systems are complex, their outcome unpredictable and notorious for extreme precipitation. 2. Few detailed studies of cut-off low events has been undertaken in the Southern Hemisphere.
3. The cut-off low this week did not result in extreme rainfall, flash flooding or infrastructure damage.
4. The lack of a strong onshore low-level flow (black southeaster) and the lack of enough surface heat thankfully contributed to the moderation of this system.
5. I spoke about the lack of "ingredients" in one of my updates. Yes, we need to have all the "ingredients" for a cut-off low to result in severe weather.
6. Eden Disaster Management issued an advisory at 12h00 on the 25/3/2014 to the effect that the public need to be aware of the fact that if it continue to rain in areas, flooding may occur in low lying areas. People living in areas prone to flooding should prepare for possible evacuation if the rain continue to fall.
7. At 14h00 (25/3/2014) it stopped raining in the Mossel Bay area and the rain started to clear from the West.
8. This was one of the strangest cut-off lows I ever observed.
9. 26mm of rain was recorded in Heiderand, Mossel Bay.
10. Rainfall of between 10 - 30mm were recorded in parts of the Western- and Southern Cape.
Even though warnings of heavy rain and flash flooding were issued and it did not materialize we should never underestimate cut-off low systems and their potential to cause disasters. Early warnings and press releases are crucial and once the "alarm" has been raised, we need to be prepared and ready for any eventuality. Examples of severe weather and destruction caused by cut-off lows: 1968 - Port Elizabeth; 1970 East London; 1981 Laingsburg; 1987 Kwazulu Natal; 2002 East London; 2003 Montagu; 2004 Southern Cape; 2005 Bredasdorp; 2006 Southern Cape; 2007 West Coast; 2007 Southern Cape; 2008 West Coast and 2008 Cape Winelands.
Finally: I would like to thank all the members of public, private sector, radio amateurs, the media and real time observers who send photos, information and reports about this event. With the information received we kept the public informed.
Once again thank you for the support and service. I am looking forward to your continued support. With your help we can render a free service to the public and hopefully contribute to save and better the lives of those in need.
Johan Terblanche
Founder: MSBWX, SAWDOS, SAWDIS
Mossel Bay
27 March 2014
