Ibiza and Formentera are under an orange weather warning for rain and thunderstorms on Thursday, September 17, as a new period of unsettled weather brings the possibility of intense rainfall, localised flooding and difficult conditions across the islands.

AEMET is forecasting rainfall accumulations of up to 50 litres per square metre in one hour, with thunderstorms potentially accompanied by strong wind gusts and hail.

The Balearic Government's emergency department is urging residents and visitors to exercise particular caution, especially around torrents, low-lying areas, roads and other locations vulnerable to sudden water accumulation.

Orange Warning for Ibiza and Formentera

The orange warning is in force throughout Thursday for Ibiza and Formentera.

The principal hazards are intense rainfall and thunderstorms, with hourly rainfall totals potentially reaching 50 litres per square metre.

AEMET's warning also allows for thunderstorms to be occasionally accompanied by strong wind gusts or hail.

The probability attached to the warning is between 40% and 70%.

Two Storm Fronts Expected

The Balearic Government says the current episode is expected to develop in two main stages.

The first front was forecast to affect the islands during the early hours of Thursday, with some of the heaviest precipitation initially expected over the sea.

A second front is expected to reach Ibiza and Formentera from around midday before moving towards Mallorca later in the day.

Authorities stress that the precise location and intensity of the heaviest rainfall can change as the storm system develops.

Localised Flooding Is the Main Concern

An orange warning does not mean that the whole island is expected to flood.

The main concern is that particularly intense storm cells could produce large amounts of rainfall over a short period, resulting in sudden water accumulation in vulnerable locations.

The Balearic Government has specifically warned residents to take care around torrents, low-lying areas and places where water can accumulate.

People are also advised not to attempt to cross flooded roads or areas covered by flowing water, either on foot or in vehicles.

Rainfall Could Reach 50 Litres in an Hour

The forecast maximum of 50 litres per square metre in one hour is significant because such concentrated rainfall can place considerable pressure on drainage systems.

However, this is a warning threshold and forecast maximum, not a prediction that every part of Ibiza will receive 50 litres.

Thunderstorms can be highly localised, meaning rainfall totals may vary substantially between different parts of the island.

Strong Winds and Hail Also Possible

Although rainfall is the main concern, the storms may occasionally bring strong wind gusts and hail.

The Balearic Government previously forecast possible gusts of between 70 and 90 km/h in parts of the episode, although it noted that winds were not expected to be as intense as during the previous weather event.

This means conditions can change rapidly, particularly underneath the strongest thunderstorms.

Authorities Advise Against Unnecessary Travel

Emergency authorities are advising people to exercise prudence and avoid unnecessary journeys during the most difficult conditions.

Drivers should take particular care on roads where water can accumulate and should never attempt to drive through flooded sections.

Authorities also advise against parking near torrents, bridges, fords or other areas vulnerable to sudden flooding.

Conditions May Vary Across Ibiza

The orange warning covers Ibiza and Formentera, but that does not mean every location will experience the same conditions.

Storm cells can produce very concentrated rainfall, with one area receiving a significant downpour while another sees much less precipitation.

The Balearic Government has noted that a substantial part of the first expected precipitation could initially fall over the sea, making the eventual impact on land dependent on the movement and development of the storm system.

A Sharp Change After the Summer Heat

The latest weather episode represents a marked change from the hot and predominantly settled conditions experienced across Ibiza during the summer.

A cold-air trough moving into the region has increased atmospheric instability and brought a significant change in weather conditions across eastern Spain and the Balearic Islands.

Temperatures are also expected to fall compared with the exceptionally warm conditions of recent weeks.

Conditions Expected to Improve

The broader weather pattern is expected to become more stable from Friday, with rainfall and storm activity gradually easing.

However, some localised showers may persist, particularly around Ibiza, before conditions become more settled.

The most important period for Ibiza and Formentera remains Thursday, when the orange warning for intense rain and thunderstorms is in force.

What Residents and Visitors Should Do

People on Ibiza and Formentera should continue checking the latest AEMET and emergency-service updates throughout the day.

Authorities recommend avoiding torrents, low-lying areas and flooded roads and not attempting to cross areas covered by flowing water.

Those who can avoid unnecessary travel during the strongest storms are advised to do so.

In an emergency, call 112.

Ibiza Faces a Potentially Difficult Weather Day

The orange warning represents a significant weather risk, but it is not a prediction that widespread flooding will occur across Ibiza.

The principal concern is intense and potentially concentrated rainfall, which could cause sudden water accumulation and localised flooding in vulnerable areas.

With two storm fronts expected to affect the Pitiusas and rainfall potentially reaching 50 litres per square metre in one hour, conditions could change quickly.

Residents and visitors should therefore remain alert, follow official warnings and take particular care around flood-prone areas throughout Thursday.