LISTEN: Do you know the 3 emergency siren sounds you'll hear in Czechia?

The usual siren test won’t sound in Prague and throughout the Czech Republic today. Amid war in Ukraine, the Czech fire service has decided to avoid stoking alarm by canceling the usual siren test. It’s also feared that running the tests would alarm Ukrainians who have only just escaped their war-torn country.

Under normal circumstances, tests take place on the first Wednesday of every month at 12 noon. This procedure is followed throughout the country except in the Olomouc region, where sirens are triggered ten minutes later to avoid disturbing the noon chimes of the city’s Astronomical Clock.

Panic over the Russian nuclear threat is already in evidence in Czechia: a webpage with advice for a nuclear emergency, launched by the State Office for Nuclear Safety, crashed within an hour of launching yesterday. Reports are also emerging of Czechs stockpiling iodine tablets, used to ward off radiation poisoning, leading to shortages in pharmacies.

This is not the first time the siren test has been canceled: sirens did not sound during major floods in the Czech Republic 2009 and 2013. They were later called off during visits by the presidents of the U.S.A. and Russia in 2010, and they were silent during the worst months of the Covid pandemic in Czechia, in April, May and November 2020.

Still, alarm over the testing of sirens might be avoided if people living in the Czech Republic were aware of the different tones used in different circumstances. Play the video below to hear the siren sounds used by the Czech emergency services.

The most familiar siren tone is the one typically used on the first Wednesday of each month to test sirens’ functionality. This tone is uninterrupted and lasts 140 seconds. It starts by rising in pitch, before sustaining its highest pitch for the duration of the test.

If a real threat to the Czech Republic emerges, you’ll hear the “general warning” siren sound, which is different to the testing sound. The general warning tone oscillates from a low pitch to a high pitch and back again throughout a 140-second period. The siren sounds three times in a row at approximately three-minute intervals.

This tone can indicate a wide of range of threats or incidents, from military invasion to evacuation due to floods. The specific nature of the emergency would be explained through radio, television, integrated rescue system vehicles or through an announcement broadcast alongside the siren tone.

If you hear a general warning siren, you should immediately hide in the nearest suitable building, which could be an office, shop or private home. Doors and windows should be closed to protect against any toxic or radioactive substances, and those hiding inside should follow TV and radio for more information about the threat.

The third sound which you might hear broadcast from Czech sirens is the fire alarm signal. This interrupted signal, consisting of 25 seconds of steady tone, followed by 10 seconds of silence, followed by another 25 seconds of steady tone, is not intended to influence public actions. It's a call for firefighters and other rescue service workers to head to their stations.