Storm Byron hit Greek capital Athens early Thursday evening with heavy rainfall and thunder, turning major roads into rivers and creating a traffic chaos.
Due to water accumulation, traffic disruptions took place on Poseidonos Avenue along the Athens Riviera, Vouliagmenis, Piraios and Hamosternas avenues, that is the usual main roads that get flooded every time in rains in the capital of Greece.
Flooding phenomena in Monastiraki, downtown Athens, and Neos Kosmos district of Athens.
Πλημμυρικά φαινόμενα στο κέντρο της Αθήνας και συγκεκριμένα στο Μοναστηράκι
Βίντεο : Stratos Jenke pic.twitter.com/MwYVPPazAw
— Forecast Weather Greece (@ForecastGreece) December 4, 2025
⚠️Σοβαρά πλημμυρικά φαινόμενα στο νέο κόσμο Αττικής αυτοκίνητα έχουνε πλημμυρίσει όπως και μαγαζιά .
Βίντεο : the https://t.co/TRelzGLyBl pic.twitter.com/wONr8uc9pT
— Forecast Weather Greece (@ForecastGreece) December 4, 2025
Also, vehicle traffic was interrupted due to an overflowing stream on the Alepochori-Schinos provincial road from the height of Mavrolimni to the Dourakou stream.
At the same time, the Fire Department received over 90 calls to evacuate motorists and passengers trapped in the waters, to pump water from homes and stores and to cut trees had had been uprooted.
According to the Fire Service, most problems were located in the southern suburbs and the center of Athens as well as in western Attica.
Video: Mandra
⛈️Μανδρα Αττικης 🌧️
⚠️Μεγάλος όγκος νερού έχει πέσει τις τελευταίες ώρες στη δυτική Αττική με μέσο όρο τα 80-100 τόνους νερού ανα στρέμμα.
Προβλήματα έχουν αρχίσει να δημιουργούνται στις παρυφές του όρους Πατέρα κοντά στη Μάνδρα.
Το βίντεο είναι από το ρέμα της Αγίας pic.twitter.com/B1bv6RgrqD— Forecast Weather Greece (@ForecastGreece) December 4, 2025
Meanwhile, emergency line <112> sent messages urging residents and visitors to avoid unnecessary movements until tomorrow, Friday, at noon.
⚠️Activation 1⃣1⃣2⃣
🆘 Warning for severe weather phenomena at intervals until tomorrow noon in the Region of #Attica. Avoid unnecessary movements. Pay attention to underground areas.
‼️Follow the instructions of the Authorities
ℹ️ https://t.co/PCgVaU15Yy@pyrosvestiki…
— 112 Greece (@112Greece) December 4, 2025
The match Olympiakos-Fenebahce has been cancelled due to floods in the premises.
The regional governor of Attica ordered the closure of primary and secondary schools as well as of kindergartens on Friday, December 5, 2025, due to the dangerous weather phenomena.
More information on the RED ALERT weather warning here on KTG.
Highest rainfall totals for 4 December were 131 mm in Vlychada and 108 mm in Avlona, Attica. These are not significant rainfall totals for one day, the flooding, as many of us know, is caused by over development, lack of and non maintained drainage and the concreting over rivers and creeks in the Athens area, from the centre to Daphne. This means normal rainy season storms cause flooding as the water has no way of being absorbed or drained, and (barely covered) new underground rivers overflow. Streets should not turn into rivers after 100 mm of rain! It is very concerning to wonder how bad the flooding will be if an extreme weather event such as an “atmospheric river” phenomenon stalls over an area, dumping thousands of millimetres of water per day, over several days.
You’re absolutely right, Evdokia. I visit Greece twice annually and I’m always shocked at how little thought is put into ‘development’. These are the consequences of that thoughtlessness. More to come. Buckle up!