Short answer. Switzerland has about 7,200 sirens, 5,000 fixed and 2,200 mobile, that sound two signals 12. The General Alarm is a regular rising and falling howl lasting one minute: a danger is possible, so listen to the radio, check the Alertswiss app and follow the authorities' instructions 2. The Water Alarm, used only below dams, means leave the area immediately 2.
What does the General Alarm sound like, and what should I do?
The General Alarm ("Allgemeiner Alarm") is "ein regelmässiger auf- und absteigender Heulton von einer Minute Dauer", a regular rising and falling howl lasting one minute 2. It means that a danger to the population is possible 2. The official instructions are to:
- Listen to the radio.
- Check Alertswiss.
- Follow the instructions of the authorities.
- Inform your neighbours 2.
The siren itself does not tell you what the danger is. The detail comes from the radio and Alertswiss 2. For the general question of staying indoors or leaving, see our guide on whether to shelter in place or evacuate.
What is the Water Alarm?
The Water Alarm ("Wasseralarm") consists of twelve low continuous tones of 20 seconds each, 10 seconds apart 2. It is used only in areas below dams, and it means you must leave the endangered area immediately ("das gefährdete Gebiet sofort verlassen") 2.
| Signal | Pattern | What to do |
|---|---|---|
| General Alarm | Regular rising and falling howl, 1 minute | Radio, Alertswiss, follow instructions, inform neighbours 2 |
| Water Alarm | 12 low continuous tones of 20 s, 10 s apart | Below dams only: leave the endangered area immediately 2 |
When is the annual siren test?
Sirens are tested on the first Wednesday of February each year. The General Alarm is tested at 13:30, and the Water Alarm between 14:00 and 16:30 1. The next test is on 3 February 2027 1. A siren heard on that day at those times is a test.
What is Alertswiss?
Alertswiss is the official app and channel of the Federal Office for Civil Protection (FOCP, German BABS) 5. It uses three levels: Alarm (red), Warning (orange) and Information, with the all-clear shown in green 5. It can send location-based push notifications and critical alerts 5.
How do I get official instructions on the radio?
The public broadcaster SRG SSR transmits official instructions through the ICARO emergency system 5. All DAB+ radios sold in Switzerland also receive FM 5, and the federal supply office recommends keeping a battery radio that receives DAB+ and FM in your emergency supply 3. Instructions are also on Teletext page 680 5. See the Swiss emergency supplies page.
Does Switzerland send alerts by Cell Broadcast?
Not yet. Cell Broadcast, which sends alerts to all phones in an area without an app, is planned but not operational 4. On 26 August 2026 the Federal Council decided to accelerate its introduction and requested a commitment credit of CHF 15.8 million in the supplementary budget II for 2026 4. On 18 September 2026 the Federal Council adopted that supplementary budget, which includes CHF 15.8 million "für die Einführung der Cell-Broadcast-Alarmierung" (for introducing Cell Broadcast alerting) 6. On 20 October 2026 the item was with the responsible parliamentary committee and had not yet been approved by Parliament 7.
Frequently asked questions
Do I have to go to a shelter when I hear the General Alarm?
The official instruction is to listen to the radio, check Alertswiss and follow the authorities' instructions 2. Shelter assignments are published only when the situation requires it; see public shelters.
What if I hear a siren on the first Wednesday of February?
At 13:30 for the General Alarm, or between 14:00 and 16:30 for the Water Alarm, it is the annual test 1.
Will I get an alert without the Alertswiss app?
The sirens and the radio reach everyone 25. Cell Broadcast, which would reach phones without an app, is not yet operational 4.
What do the Alertswiss colours mean?
Red is Alarm, orange is Warning, and green signals the all-clear; there is also an Information level 5.
Sources
- Bundesamt für Bevölkerungsschutz BABS — Der jährliche Sirenentest — https://www.babs.admin.ch/de/sirenentest (accessed 2026-10-20)
- Alertswiss (BABS) — Bei Gefahr richtig reagieren — https://www.alert.swiss/de/vorsorge/bei-gefahr-richtig-reagieren.html (accessed 2026-10-20)
- Bundesamt für wirtschaftliche Landesversorgung BWL — Kluger Rat – Notvorrat — https://www.bwl.admin.ch/de/kluger-rat-notvorrat (accessed 2026-10-20)
- Bundesamt für Bevölkerungsschutz BABS — Alarmierung der Bevölkerung: Bundesrat beschleunigt Einführung von Cell Broadcast — https://www.babs.admin.ch/de/newnsb/wr3dPx9UizGyBGsWyzBr7 (accessed 2026-10-20)
- Alertswiss (BABS) — FAQ — https://www.alert.swiss/de/faq.html (accessed 2026-10-20)
- Der Bundesrat (admin.ch) — Bundesrat verabschiedet Nachtrag II zum Voranschlag 2026 — https://www.admin.ch/de/newnsb/c6x2tCSsxAoq (accessed 2026-10-20)
- Die Bundesversammlung – Das Schweizer Parlament — Voranschlag 2026. Nachtrag II (Geschäft 26.042) — https://ws-old.parlament.ch/affairs/20260042 (accessed 2026-10-20)
Turn this into action
Your plan for Switzerland, worked out for your household.
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- Phaenyx Safe: one tap to tell your people you are safe
Sources
- Bundesamt für Bevölkerungsschutz BABS · Der jährliche Sirenentest checked 2026-10-20
- Alertswiss (BABS) · Bei Gefahr richtig reagieren checked 2026-10-20
- Bundesamt für wirtschaftliche Landesversorgung BWL · Kluger Rat – Notvorrat checked 2026-10-20
- Bundesamt für Bevölkerungsschutz BABS · Alarmierung der Bevölkerung: Bundesrat beschleunigt Einführung von Cell Broadcast checked 2026-10-20
- Alertswiss (BABS) · FAQ checked 2026-10-20
- Der Bundesrat (admin.ch) · Bundesrat verabschiedet Nachtrag II zum Voranschlag 2026 checked 2026-10-20
- Die Bundesversammlung – Das Schweizer Parlament · Voranschlag 2026. Nachtrag II (Geschäft 26.042) checked 2026-10-20