Skip to content Skip to left sidebar Skip to footer

5 May 2021 Weather Alert: Impact Based Weather Warnings for Western Cape and Namaqua

Weather Alert: Impact Based Weather Warnings for Western Cape and Namaqua – 5 May 2021

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)
Disruptive Rain Yellow(L4) Breede Valley, City of Cape Town, Drakenstein, Hessequa, Langeberg, Stellenbosch 05/05/21 –  20h00 06/05/21 –  23h00

Discussion: An upper air driven system is causing showers and thundershowers 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 over the City of Cape Town, Cape Winelands (mainly central and southern) as well as Hessequa municipality from Wednesday evening and intermittently throughout Thursday, where rainfall accumulations between 40-60mm reaching up to 80-100mm in the mountainous areas can be expected. With the thunderstorms, there is a small chance of hail. Lightning will occur as well as strong winds over short periods as a result of thunderstorm downburst.

Impact: Flooding of roads and settlements in both formal and informal settlements is likely which 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 Thursday. 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. 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, Cape Agulhas, City of Cape town, Hessequa, Overstrand 05/05/21 –  18h00 06/05/21 – 23h00

Discussion: Strong to gale force south-easterly winds (50-70km/h) and gusts up to 80-90km/h is expected from Wednesday afternoon offshore between Hout Bay and Stilbaai. 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 and result in small vessel at risk of taking on water and capsizing in totality.

Instruction: 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.

Hazard Alert Level Affected Municipalities Valid from (SAST) Valid to (SAST)
Damaging Winds Yellow(L4) Cape Agulhas, Cape Agulhas, City of Cape town, Hessequa, Overstrand 05/05/21 –  18h00 06/05/21 – 23h00

Discussion: Wave heights between 4.0-5.5m is expected between Hout Bay and Stilbaai from Wednesday late morning continuing into Thursday. Along with these higher wave heights, predominant southerly to south-easterly swells are also expected. Strong southerly winds (50-70km/h) is expected along the between Hout Bay and Stillbaai from Wednesday afternoon and throughout Thursday.

Impact: Small vessels will experience difficulty in navigation at sea as a result of rough and choppy seas (quick successive, steep waves) and may be at risk of taking on water and capsizing in a locality. Localized disruptions to beachfront activities.

Instruction: Be aware of large waves along the coastline. Small vessels are advised to seek shelter in harbours, bays or inlets. Refrain from any beachfront activity.