Eastern Slovenia receiving most of the precipitation, increased risk of landslides
Meteorologist Branko Gregorčič initially noted that, as it was already mentioned yesterday, that the event would feature two parts - yesterday's and today's events. Yesterday's event featured very intense localised downpours. The heaviest downpours mainly hit the Slovenian Istria, Karst, Goriška, Vipava Valley, as well as central Slovenia and Ljubljana and its surroundings. Today's event is still under the influence of a cyclone, which still hovers above the northern Mediterranean, but the direction of the high-altitude winds has turned towards the south-east, so that very moist air with south-eastern winds is reaching Slovenia today (via Croatia). As it rises along the mountain barriers towards the sub-Alpine and Alpine areas, moisture condenses and creates precipitation, which is expected to be the heaviest this afternoon and evening, and to continue until tomorrow morning.
The east of Slovenia will receive most of the precipitation, especially in the regions of Zasavje, Savinja, Podravje, Koroška and also a considerable part of Štajerska. In these areas, ARSO expects rainfall of between 50 and 80, possibly even close to one hundred litres per square metre in some localities. ARSO also notes that this type of precipitation will be steady, especially over large areas, and that really extreme downpours are not expected, so the impact on the watercourses will be somewhat slower. However, the saturation of the soil will continue to increase and, consequently, other types of risks will increase, meteorologist Gregorčič said.
Hydrologist Janez Polajnar said that this second wave of precipitation would fall on already soaked ground, which is a cause for concern in areas that are already vulnerable. While between 40 and 50 litres of rain per square metre fell in the regions of Koroška and Savinja yesterday, a similar or even slightly greater amount of precipitation will fall today on ground that is already saturated. This is the reason why torrential streams may swell up further, and why rainwater will spill over. Because this area is already affected, ARSO cannot forecast exactly how and where this water will flow, so extra caution is advised for these areas today.
Polajnar said that, in addition to the already mentioned vulnerable areas, the Drava River is flooding in its lower course below the Markovci Dam. At night the discharge was around 1,100 cubic metres per second and now this high water wave is moving across Slovenia.
He also said that the Mura River was expected to spill over, but, as it appears, within levees in the usual areas. During the day, small torrential watercourses are expected to spill over, including in Zasavje and in the area of sub-Alpine hills. At the end, hydrologist Polajnar noted that today's event was focused on vulnerable areas in the regions of Koroška, Savinja and the Slovenske Gorice Hills, where rainwater could cause flooding in unusual places, while torrential watercourses could also become swollen.
Slovenian Water Agency director Neža Kodre said that watercourses on the coast caused the most problems yesterday during the day, with torrential streams in Izola, Koper and Piran spilling over due to the stormwater. There were no major interventions on watercourses overnight. She said that all services were on high alert, and that members of the Water Agency and utilities were still on the ground. Kodre noted that the services would continue to be on duty with a higher number of staff and be prepared for possible emergency measures, depending on the developments on the ground.
"The ground is extremely wet, so there is an increased risk of landslides. Including in areas that have not been affected so far," noted the director of the Geological Survey of Slovenia, Miloš Bavec. He stressed that special attention should be paid to areas that have already been affected, as the risk of landslides is further increased in these areas. He also noted that the increased risk of landslides being triggered would not end with the cessation of the rain, but would remain for several hours, most likely even days.
Srečko Šestan, the commander of the Civil Protection Service, meanwhile spoke about the use of sirens. As he explained, it was proposed yesterday that municipalities use sirens to alarm the public, and to "tell the residents in advance, for periods when precipitation is forecast, that the sirens will be blown for this purpose". By doing so, they will, among other things, avoid confusion among people, as they will not have to search for information online and call 112 for explanations.