Red alert for northwest Slovenia and orange alert for other parts of the country
The expected extreme meteorological and hydrological conditions in Slovenia were presented at the press conference by meteorologist Branko Gregorčič and hydrologist Janez Polajnar, both from the Slovenian Environment Agency (ARSO), Director of the Slovenian Water Agency Neža Kodre, Commander of the Civil Protection of the Republic of Slovenia Srečko Šestan, and Director of the Geological Survey of Slovenia Miloš Bavec.
The speakers said that the bulk of the stormy weather will occur overnight, from tonight until early morning, when autumn floods and an extremely fast rising of water levels are expected. They urged the competent services and Slovenia's residents to remove fallen leaves from their yards and streets to prevent blocking of drainage channels and flooding during the forecast heavy rainfall. They also urged people to take precautionary and self-protection measures ahead of the storm by moving their belongings to higher floors of their homes and their cars to safer areas. People are also advised to strictly follow the instruction of the members of civil protection services and other competent services and to take precautions to protect themselves and their lives in the event of an emergency.
Meteorologist Brane Gregorčič presented the latest weather situation. He explained that cyclones have become more frequent over the North Atlantic this autumn, and that today we are witnessing one of the deepest in recent decades, which has already reached the south of the British Isles and is already affecting the weather in France. A cold front is rapidly approaching the Alps and is expected to cross Slovenia in the middle of the night. Ahead of the front, we can also expect an increased inflow of moist and warm air from the south/south-west. In the evening, precipitation is expected to intensify rapidly. Strong southerly winds with gusts of 70–100 kilometres per hour will blow along the coast. Already before the front, the heaviest rainfall is expected in the Julian Alps with more than 100 litres of rain per square metre falling within six hours, and later, during the front, the heavy rainfall will move across Slovenia during the night. Heavy rain and gusty winds are expected across the whole of Slovenia. Rainfall accumulation will be highest in the wider region of Posočje, Bohinj and the Upper Sava Valley, where very strong winds will blow at high altitudes. Between 120 and 240 litres of rain per square metre are expected to fall in northern Slovenia over the next 24 hours, which is the reason for issuing the highest alert level, i.e. the red alert, Gregorčič stressed, adding that the most of the stormy weather will occur overnight, from tonight until early Friday morning.
Hydrologist Janez Polajnar said that tonight and tomorrow autumn floods were expected and he warned of extremely fast rising waters. The heavy rainfall will lead to a rapid increase in river levels, especially in northwest Slovenia, potentially resulting in more extensive flooding in certain areas. Torrential streams will rise very rapidly in the upper and middle Posočje region, the Idrija-Cerklje hills, the Idrijca river basin, the Bače settlement, in the areas of pre-Alpine hills, the two Sora rivers, especially the Selška Sora river, and also in the Upper Sava Valley. This torrential outflow will fill the channels of the major rivers throughout tomorrow morning and during the day. The Sava river, as one of the main drainage watercourses for this rainfall, is expected to rise rapidly in the early hours of tomorrow morning. Already tonight and in the early hours of the morning, the flow of the Sava will reach between 1200 and 1500, possibly even 1600 cubic metres per second, in Ljubljana's surroundings. Torrential outflows and stagnation of rainwater are possible in the Vipava Valley, the Pokolpje basin and on the coast. Flooding of the Drava river is expected throughout the day tomorrow, especially in its lower reaches.
Neža Kodre, Director of the Slovenian Water Agency, said that emergency measures were still being implemented on watercourses across Slovenia. As many as 212 teams are currently on the ground cleaning, working to restore the flow of watercourses while implementing other necessary preventive measures. Late this afternoon, teams will be on duty, monitoring water levels and taking emergency measures to prevent damage and mitigate the potential hazards caused by flooding. She urged Slovenia's residents to remove all materials that could be swept away by the water, such as hay bales, firewood, etc.
Civil Protection Commander Srečko Šestan again called on the competent services and Slovenia's residents to clear drains of fallen leaves to prevent local flooding. He also announced that the competent services throughout Slovenia, with the exception of Prekmurje, had been put on high alert. Members of the Slovenian Armed Forces and their machinery will also be on standby.
Director of the Geological Survey of Slovenia Miloš Bavec stressed that the situation is further exacerbated today by the anticipated exrtraordinary rainfall in the Julian Alps and their foothills, along with the already soggy ground, which increases the risk of landslides. In addition to the areas where the rainfall is expected to be heaviest, he also drew attention to the areas already affected, in particular in the Kamnik-Savinja Alps, the Karavanke Mountains and their wider adjacent area. In order to prevent the reactivation of individual landslides, which can easily occur, he called for cleaning the drains that have already been set up to drain specific landslides and for diverting water from gutters away from landslides. Where possible, landslides and their breakaway edges should be covered with foils, Bavec warned.