River surges, flooding in cities, and even local floods – these are the threats that IMGW lists in its weather alert for southwestern Poland. The Genoese low Boris will bring extreme precipitation to our region.
After dry weeks – let us recall that we have hydrological drought on a large part of Poland's rivers, and in Warsaw and a dozen other places a record low water level was broken – we are dealing with a sudden weather threat. This is a very dangerous pattern, which is intensified by climate change.
Southern Poland at risk of flooding
The Institute of Meteorology and Water Management has issued third-degree weather warnings for parts of the Lower Silesia, Opole and Silesian voivodeships (you can check the current forecast and alerts for your place of residence on the IMWM website). Alerts 2 and 1 are also in effect in central Poland.
As explained by IMGW, the very heavy rainfall will be caused by a humid maritime polar air mass and the so-called Genoese low, called Boris. Genoese lows usually bring very heavy rainfall – such a weather system was responsible for the rainfall that led to the “flood of the millennium” in 1997. This does not mean that the situation will repeat itself one to one, but the threat in some regions will be very serious.
In the Lower Silesian, Opole and Silesian provinces, a total of up to 150 l/m2 is forecast from Thursday to Sunday. However, if we look at weather models, in some places it could be much more – 200, or even 300 l/m2. For comparison, the annual average rainfall in the region is around 600 mm (or 600 litres per square metre).
When we look at weather models, the heaviest rainfall is expected to occur on the Polish-Czech border, especially in the Kłodzko Valley. Importantly, forecasting such rainfall with very high accuracy is difficult – it may turn out that the most intense rainfall will occur in a different place than the models show. Therefore, residents of the entire region should prepare for dangerous weather. Depending on where exactly the most rain falls, in the coming days there may be floods further downstream – therefore, it is necessary to follow hydrological forecasts and warnings on an ongoing basis.
Floods and local floods
Thursday is already forecast to be rainy in the south-west of the country, but really heavy rain will appear on Friday and Saturday, with heavy rain still on Sunday. Strong, gusty winds are also possible.
How rapidly the water level in rivers in the region will change is shown in the forecast for the Biała Głuchołaska River in Głuchołazy. What is very important – we are talking about a mountain river, and as we have already mentioned, there is no 100 percent certainty where the rainfall will be the heaviest. Therefore, the described forecast is not certain, however gives an idea of the scale of the threat in the region.
On Thursday morning, the water level in the river was low (approx. 30 cm), and the flow was slightly over 1 meter per second. According to the hydrological forecast, the water level will rise to over 300 cm by Sunday (the absolute maximum from the “flood of the millennium” in 1997 was 380 cm), and the flow will increase to 350 m/s. For comparison, the flow in the Vistula in Warsaw on Thursday was slightly over 200 m/s. The current forecast can be checked on the website hydro.imgw.pl
Events are being cancelled in the region, and on Thursday morning a meeting of the Municipal Crisis Management Team was held at the Głuchołazy City Hall.
Alerts in Czech Republic and Austria
The same weather pattern will bring very heavy rainfall to Slovenia this week, Austria and the Czech Republic.
In our southern neighbors, the highest level of weather warnings are in effect for almost the entire country. The local meteorological services are warning of very heavy rainfall and a significant increase in water levels in rivers.
– The situation that awaits us in the coming days will probably be similar to what we experienced in 1997 and 2002 – he said Environment Minister Petr Hladík. Where does he expect the worst situation?
The situation is also complicated by strong winds, which, due to the soaking of the soil, may cause trees to fall and landslides. The worst situation should be in the Jeseníky Mountains (close to the border with Poland – ed.), where according to the optimistic scenario, 395 mm of precipitation should fall, in the case of the negative scenario 452 mm. Not only areas near rivers are at risk, flash floods may also cause damage in valleys and on slopes.
In Austria predicted There is a lot of rain and snow in the higher parts of the mountains, which could lead to rivers overflowing and mudslides. The Vienna area and other parts of the country could see well over 200 mm of rain in the next few days.
The Ministry of Defense there has put army on standby so that, if necessary, soldiers can support civil services in dealing with the effects of the rainfall – the portal reports courier.at.