Short answer. In South Africa, weather warnings come from the South African Weather Service (SAWS) as impact-based colour levels: green, yellow, amber and red 1. They are spread by radio, television, newspapers, social media and WhatsApp, and the NDMC says to always verify alerts through SAWS 1. Around Koeberg, sirens cover the 16 km zone 2. No national cell broadcast system was found in use 3.
What do the warning colours mean?
| Level | Meaning |
|---|---|
| Green | No expected severe weather 1 |
| Yellow | Be aware: moderate risk of severe or low risk of extreme weather. Stay alert 1 |
| Amber | Be prepared: high risk of severe or moderate risk of extreme weather. Remain vigilant 1 |
| Red | Take action: high risk of extreme weather. Follow instructions from the authorities under all circumstances 1 |
How do warnings reach people?
The NDMC lists social media (Facebook, X, WhatsApp), newspapers, television, more than 140 radio stations and SAWS platforms 1. Because warnings circulate widely, the NDMC advises always verifying an alert through SAWS 1. SAWS also promotes its WeatherSMART app for warnings 4.
A battery-powered radio with spare batteries is on the City of Cape Town kit list (see the official kit page). Our emergency radio guide explains what to look for.
Does South Africa use cell broadcast alerts?
Not nationally. A 2024 CSIR study says the use of cell broadcast and location-based SMS by authorities "is still an area of improvement" 3. Do not rely on an automatic phone alert: follow radio, TV and SAWS channels.
How do the Koeberg sirens work?
A siren and loudspeaker system covers the zone around Koeberg Nuclear Power Station, including Atlantis, Duynefontein, Melkbosstrand, Van Riebeeckstrand, Philadelphia, Bloubergstrand, Bloubergrant, West Beach, Sunningdale, Parklands, Robben Island and surrounding farms 2.
Eskom is explicit: "Hearing a siren alarm tone or announcement does not mean you should evacuate" 2. A siren means turn on the radio and listen for instructions. Residents can confirm a siren with the City of Cape Town Disaster Operations Centre on 021 597 6000 2.
When are the sirens tested?
The sirens have a weekly silent ("quiet") test and an annual full-volume test of about two hours. In 2026 it took place on 3 March, with individual sirens re-tested on 4-5 March if needed, and it is announced over the public address system 2.
Frequently asked questions
Does a siren near Koeberg mean I must leave?
No. Turn on the radio and follow instructions; Eskom states a siren does not mean you should evacuate 2. See the iodine page for the Koeberg zones.
What should I do at a red warning?
Take action and follow instructions from the authorities under all circumstances 1.
How can I check whether a warning is real?
Verify it through SAWS, as the NDMC advises 1.
Will my phone receive an emergency alert?
No national cell broadcast system was found in use 3. Rely on radio, TV and SAWS channels.
Sources
- National Disaster Management Centre — Early Warning Systems (EWS) — https://www.ndmc.gov.za/brochures/Electronic-Brochure.pdf (accessed 2026-10-20)
- Eskom — 2026 Koeberg Nuclear Power Station Emergency Plan Calendar — https://www.eskom.co.za/wp-content/uploads/2026/01/141-25-Koeberg-Eskom-Calendar-2026.pdf (accessed 2026-10-20)
- CSIR (Council for Scientific and Industrial Research) — CSIR research paper on emergency alert systems in South Africa (ICEGOV 2024) — https://researchspace.csir.co.za/bitstreams/bb3ea198-734a-40c0-ba4a-91a744a31b36/download (accessed 2026-10-20)
- SAnews (Government Communication and Information System), 1 April 2026 — SAWS warns of scattered showers ahead of Easter travel period — https://www.sanews.gov.za/node/80598 (accessed 2026-10-20)
Turn this into action
Your plan for South Africa, worked out for your household.
- Water, food and equipment counted for each person and pet
- The nuclear plants and zones around your home
- Phaenyx Safe: one tap to tell your people you are safe
Sources
- National Disaster Management Centre · Early Warning Systems (EWS) checked 2026-10-20
- Eskom · 2026 Koeberg Nuclear Power Station Emergency Plan Calendar checked 2026-10-20
- CSIR (Council for Scientific and Industrial Research) · CSIR research paper on emergency alert systems in South Africa (ICEGOV 2024) checked 2026-10-20
- SAnews (Government Communication and Information System), 1 April 2026 · SAWS warns of scattered showers ahead of Easter travel period checked 2026-10-20