The flooding began in Austria and the Czech Republic, then spread to Poland, Romania and Slovakia, and then onwards to Germany and Hungary.

[14] A dam failure in Sankt Pölten flooded the city, leaving 1.500 people without functioning sewers.

[15] In the Alpine regions, the heavy rains turned into snowfall, causing an extremely early onset of winter conditions.

[23] On 15 September, Martin Kupka, the Czech transport minister, announced that railway operations in the Moravian-Silesian Region will remain suspended for at least a week to eliminate the damage caused by heavy rain and following floods.

[27] Boris hovered over southwestern Poland, where it dropped almost half a year worth of rain during three days.

[28][29] Severe flooding alerts were reached in 82 measuring stations, primarily in the Oder river basin.

[30] On 14 September, in the town of Głuchołazy, water overwhelmed flood barriers and destroyed a temporary bridge on the Bělá river, leading to mandatory evacuations.

[37] Later in the same evening, the dam in Stronie Śląskie failed, causing torrents strong enough to completely destroy homes.

[44] The same day, the flood wave reached Szprotawa, where authorities called for evacuations of parts of the town.

[47] On 18 September, there was partial flooding in the neighborhoods of Marszowice, Stabłowice and Złotniki in Wrocław, however, for the most part, houses and apartment blocks were spared thanks to anti-flood embankments built in the meantime.

[53][54] Galați and Vaslui Counties were severely impacted by the floods caused by Storm Boris, with multiple villages submerged, key infrastructure damaged, and thousands of residents displaced.

Several villages were overwhelmed by the flooding, including Slobozia Conachi, Cudalbi, Pechea, Costache Negri, Grivița, and Piscu.

Several local rivers breached their banks, turning farmlands and residential areas into flooded zones, further complicating rescue operations.

[57] After a strong wind on the night of 14 to 15 September 2024, which was preceded by several days of heavy rains, water streams in Slovakia also rose.

The Blatina brook overflowed and flooded the parking lot and the underground of an apartment building in Sídlisko Sever II, Pezinok.

[58] At noon on 16 September, the level of the Danube reached a height of 926 centimeters and overflowed onto the Tyrš and Fajnor Embankments in Bratislava.

[66] As of 17 September, 500 kilometres (310 mi) of the Danube is under flood warnings in preparation due to rising waters.