4 May 2021 Weather Alert: Impact Based Weather Warnings for Western Cape and Namaqua
Please find included several Impact Based Warnings for the Western Cape and Namaqua Region of Northern Cape
Legal notice:
“This warning from SA Weather Service must be communicated as received and may not be altered under any circumstance.
It must be forwarded or communicated in its entirety and no portion hereof may be replicated or copied and distributed.”
| Hazard |
Alert Level |
Affected Municipalities |
Valid from (SAST) |
Valid to (SAST) |
| Damaging Waves |
Yellow (L1) |
Cape Agulhas, Cape Agulhas, City of Cape town, Hessequa, Overstrand, Saldanha Bay, Swartland, Table Bay |
05/05/21 – 08h00 |
06/05/21 – 00h00 |
Discussion: An upper air driven system is causing considerable rain and showers to develop over the south-western parts of the Western Cape from tomorrow morning spreading eastwards over the rest of the province during the afternoon and evening. Rain continues for the south coastal areas on Thursday and Friday. With this system wave, heights are expected to reach 4.0-5.5m between Cape Columbine and Stilbaai from Wednesday afternoon into Thursday. Along with these higher wave heights, predominant southerly to south-easterly swells are also expected. Strong southerly winds 60-80km/h) is expected along the west and south-west coastal areas from Wednesday early morning spreading to Still Bay by evening and continuing into Thursday. Please note that there is high uncertainty with this system and models have not been consistent. We will continue to monitor the conditions and update warnings.
Impact: Small vessels can possibly be at risk of taking on water and capsizing in a locality. There is also a possibility of difficulty in navigation such as small vessels in a short period and steep waves. Localized disruptions to beachfront activities such as the closure of beaches for swimming can also be expected.
Instruction: Be aware of large unpredictable waves along the coast. Small vessels are advised to seek shelter in harbours, bays or inlets. Be aware of strong rip currents especially during spring tides.
| Hazard |
Alert Level |
Affected Municipalities |
Valid from (SAST) |
Valid to (SAST) |
| Disruptive Rain |
Yellow (L4) |
Bitou, Breede Valley, City of Cape Town, Drakenstein, George, Hessequa, Knysna, Langeberg, Mossel Bay, Stellenbosch, Witzenberg |
05/05/21 – 20h00 |
06/05/21 – 00h00 |
Discussion: An upper air driven system is causing rain and showers to develop over the south-western parts of the Western Cape on Wednesday morning spreading eastwards to the rest of the province during the afternoon and evening. Significant rainfall can be expected in the Overberg, Garden Route and the City of Cape Town from Wednesday afternoon into Thursday, where rainfall accumulations of between 40-60mm reaching up to 80-100mm in the mountainous areas can be expected. A further 05-10mm can be expected on Friday for the same areas. We will continue to monitor the conditions and update warnings.
Impact: Flooding of roads and settlements in both formal and informal settlements are possible that could result in damage to property and infrastructure. Disruption of traffic flow is likely, along with increased motor vehicle accidents, especially in peak hour traffic on Wednesday. Essential services such as water and electricity may be affected. There is a chance for mudslides and rockfalls in susceptible areas.
Instruction: Be cautious on the roads and avoid crossing rivers and swollen streams where water is above your ankles. If trapped in a vehicle during a flood, abandon it and climb to higher ground. In buildings, move valuables to a safe place above the expected flood level. Switch off electricity at the supply point to the building. NEVER drive on a road covered by water. If the vehicle stalls, leave it immediately and seek higher ground. Be especially cautious at night when it’s harder to recognize flood dangers. Listen to the radio or TV for warnings and obey the instructions from disaster management officers.
| Hazard |
Alert Level |
Affected Municipalities |
Valid from (SAST) |
Valid to (SAST) |
| Damaging Winds |
Yellow (L4) |
Cape Agulhas, City of Cape Town, Cape Agulhas, Cape Agulhas, City of Cape town, Hessequa, Overstrand, Saldanha Bay, Swartland, Table Bay, Overstrand |
05/05/21 – 18h00 |
06/05/21 – 00h00 |
Discussion: Strong to gale force south-easterly wind of 62-70km/h and gusts up to 80-90km/h is expected from Wednesday late morning along the coastlines between Cape Columbine and Stilbaai, including the Cape Metropole and Overberg during the afternoon. The wind will be at its full force from Wednesday night into Thursday morning, this is the same period when the upper air weather system will be intensifying.
Impact: Strong winds will cause danger to navigation out at sea. Some disruption to operations for small harbours and ports may occur, and also disruptions to beachfront activities are possible. Inland: strong winds will result in dangerous driving conditions, damage to settlements, falling of trees and interruptions to power lines and communications.
Instruction: Stay indoors where possible away from the windows that open towards the severe winds. Be aware of the following: – sudden crosswinds if travelling especially between buildings, fallen trees or power lines and flying debris. Small boats must stay away from the open sea and seek the shelter of a harbour, river estuary or protected bay Parked aircraft should be pointed into the direction of the wind and secured. Ensure that all temporary structures are well anchored.
>>>Legal notice:<<<
“This warning from SA Weather Service must be communicated as received and may not be altered under any circumstance.
It must be forwarded or communicated in its entirety and no portion hereof may be replicated or copied and distributed.”
Report any weather related incidents to the Garden Route Disaster Management Centre at:
044 805 5071.
