Heavy rains and flood in Poland. Are we facing a catastrophe?

The upcoming weekend will bring exceptionally intense rainfall in Poland due to the influence of a Genoa low. Forecasts indicate very high precipitation amounts, which creates the risk of urban floods and river floods in many regions of the country. The Boris low appeared on Thursday and will remain until Sunday. IMGW-PIB (Institute of Meteorology and Water Management) regularly updates hydrological warnings, especially concerning the most endangered areas. Where can the biggest damage occur?

Genoa low over Central Europe

The Genoa low, which forms over the Gulf of Genoa due to the clash of warm air masses from the Mediterranean Sea and northern winds from the Alps, then moves over the Czech Republic, Slovakia, Germany, and Poland. The Czech Meteorological Institute issued a warning yesterday, predicting that between 150-250 mm of rain will fall in the southeastern part of the country by Sunday. In Poland, the situation will be just as dramatic.

According to the IMGW-PIB forecast, daily precipitation in the Lower Silesian and Opole voivodeships will reach 60-70 mm on Friday. On Saturday, in Lower Silesia, Opole, Silesia, and Lesser Poland, 50-120 mm may fall within 24 hours. Thunderstorms and strong wind gusts up to 90 km/h may accompany the downpours. Rain will continue on Sunday, but the intensity will decrease, with 60-80 mm of rainfall expected in Lower Silesia and Lublin voivodeships. Overall, numerical models predict that by Monday morning, 250-400 mm could fall in the Nysa Kłodzka catchment area, while 200-300 mm could fall in the Small Vistula region.

Flood in Poland increasingly likely

On Thursday evening, IMGW-PIB reported that the heaviest rainfall had been recorded in the western part of the Lower Silesian voivodeship and the south of the Opole voivodeship. At the same time, warning levels were reached at three stations in the Oder river basin, and high water zones were locally observed on the left tributaries of the Oder.

During the night and early morning, residents of eastern Lublin and southern Subcarpathia faced thick fogs, reducing visibility to 200 meters. By 6:00 AM in Międzylesie, rainfall was recorded at 61 mm, and in Dzierżoniów and Głuchołazy, 58 mm. Rivers have already begun to rise, making the flood scenario in Poland a reality.

In Odolanów on the Barycz river, the water level exceeded the alarm threshold by 5 cm, and by Saturday, it is expected to rise by another 140 cm. Warning levels were exceeded on the Ślęza, Swędrnia, Orla, Kwisa, and Bystrzyca Dusznicka rivers. IMGW-PIB’s hydrological forecasts predict that on Sunday in Korzeńsko, the water level could rise to 500 cm, exceeding the previous maximum by 117 cm! Flooding with alarm level exceedances is predicted for the area from Leszno and Jelenia Góra in the west to Nowy Sącz and Tarnów in the east of the country.

In Wrocław, preparations for the expected flood have been undertaken by the Road and City Maintenance Board (ZDiUM) and the Municipal Water Supply and Sewerage Company (MPWiK). According to the city’s information portal, stormwater drains were inspected, emergency drainage teams were prepared, and retention tanks were emptied. But will it be enough?

We will find out on Monday, but it’s important to realize that even well-planned and maintained infrastructure has its capacity limits. In most Polish cities, the stormwater drainage system is outdated and poorly maintained, which increases the risk of disaster.

It was drought, now it’s flood – how is it possible?

Just four days ago, we wrote about hydrological drought, and now the number one topic is the expected flood in Poland. This paradox may be surprising. Flash floods, which are increasingly troubling cities worldwide, are a result of deepening climate change and the level of urbanization. Most city surfaces today are streets, sidewalks, and parking lots – sealed surfaces that do not absorb water but direct it to the stormwater system. However, infrastructure is designed based on average rainfall and cannot cope with the downpours that have now descended upon Poland.

Another problem is the limited absorption capacity of dry soil. This phenomenon was well explained in an experiment by Dr. Rob Thompson from the University of Reading. During a hydrological drought, even surfaces that are not paved become poorly permeable, and most rainfall runs off them. The consequences of the expected flood in Poland may therefore be greater due to prolonged water shortages.