Storm alerts in Croatia — will they reach a tourist, and where to shelter

Croatia uses HR-Alert, built on Cell Broadcast technology. That distinction matters: Cell Broadcast is not an SMS. The message is broadcast to every handset registered to a particular network cell — regardless of operator, regardless of which country the SIM comes from, and with no internet connection required. A foreign SIM roaming in Croatia receives it exactly as a Croatian one does.

There are two caveats worth knowing in advance.

First, the trigger threshold. HR-Alert is not sent for every storm. It is reserved for large-scale events: flash floods, fires threatening settlements, disasters. An ordinary afternoon storm over Makarska, even with a downpour, usually does not cross that threshold.

Second, language. Alerts arrive in Croatian, often with an English note appended. Routine weather warnings are issued by DHMZ, the Croatian meteorological service, and published on its own pages and via Meteoalarm — in Croatian, in places the average visitor never visits.

The practical conclusion is uncomfortable but needs saying plainly: on an ordinary day, nobody will warn you. An alert will arrive for an extreme event. For a normal violent storm you are relying on your own observation and on a forecast you check yourself.

One thing worth doing on arrival: check that emergency alerts are not switched off in your phone settings. They are sometimes disabled by default, or by the user after a run of system tests. It is the only channel that reaches you without any knowledge of the language.

A beach is one of the worst places to sit out a storm, because a person standing on open shore is the highest point around.

• Best: a solid building — a bar, campsite reception, a shop. Walls and wiring carry the charge away.
• Very good: a car with the windows closed. The bodywork acts as a Faraday cage. Do not touch metal parts of the interior.
• Bad: a beach umbrella. A metal pole in the open is exactly what to avoid. Take it down and walk away.
• Bad: a lone tree or a small group of trees by the shore. A discharge can jump from the trunk to a person standing beside it.
• Very bad: a tent. The fabric protects against nothing and the poles are often metal. At a campsite, go to the sanitary block or your car.

If you have no shelter at all: crouch, feet together, hands on knees, ideally on something insulating such as a backpack or a sleeping mat. Do not lie down. The aim is to minimise contact with the ground, because a substantial share of casualties are caused not by a direct strike but by step voltage spreading through the earth.

Many sailors on the Adriatic ask this, and the answer is unambiguous: no, being on the water is considerably worse.

The reason is simple. A sailing boat on open water is a mast — often aluminium, a dozen metres or more — protruding above a flat surface for kilometres around. From the point of view of a discharge it is a textbook initiation point. The vessel is not safer for being on water; it is more exposed precisely because of it.

Then there are hazards that do not exist on land:

• Squall. A sudden gust on the leading edge of a storm cell can go from calm to 30–40 knots in seconds. Adriatic squalls are notoriously abrupt, and a boat with sails up can be knocked flat.
• Sea state. The short, steep wind-driven chop of the Adriatic builds very fast and is harder on a small vessel than an ocean swell.
• Loss of electronics. A strike can destroy GPS, radio and navigation lights — that is, everything you would use to call for help.

The working rule: if the forecast indicates storms, do not go out. If you are already on the water and see a cell developing, head for port or a sheltered bay immediately, not "once it gets closer". Distances between Adriatic marinas can be considerable, and a cell develops in 30 to 60 minutes. A quarter of an hour of hesitation is decisive.

On deck during a storm: go below, do not touch the mast, shrouds or rails, put on lifejackets, and keep time outside to a minimum.

This section repeats across all our storm articles, because it is the most important and the most often ignored.

During heavy rain do not stay by a river and do not descend into a narrow valley. In Croatia this concerns the streams draining the Velebit, Biokovo and the hills above Dubrovnik. Mountain watercourses rise within minutes, and the surge comes from rain that fell several kilometres upstream — the sun may be shining where you are. A dry bujica channel you crossed in the morning can be impassable by afternoon.

• Do not park in a dry channel or at its outlet to the sea — the most common cause of flooded cars in Dalmatia.
• Do not drive into water on the road. Thirty centimetres is enough to float a car. More than half of flash-flood fatalities occur in vehicles.
• Move to higher ground early, as the level begins to rise — not during.
• Avoid underpasses and underground car parks in Split and Dubrovnik when heavy rain is forecast.

In a life-threatening emergency call 112 — it works across the EU, even without a SIM card and from a locked phone, and operators take calls in English.

Since there is no point counting on an official warning for an ordinary storm, checking the forecast yourself is what remains — ideally the evening before a planned day on the water or the beach.

Our tool gives a point forecast for a specific town: start time, peak, duration, lightning signal strength, and separately the chance the cell passes you by. You enter Split, Zadar, Makarska, Dubrovnik or any smaller coastal place.

The caveat we repeat in every article: the ICON model has a grid of a few kilometres and, along such a narrow mountainous coastal strip, captures the relief only partially. It will tell you a storm situation is developing and roughly when — not whether your bay or the next one takes the hit. For planning a day, that is still an order of magnitude better than "storms possible in Dalmatia".

• Storms in Croatia and local flooding — Dubrovnik, Split, Zadar
• Check the storm for your location