Daniel was a multi-day extreme-rainfall episode. The slow-moving system kept heavy rain over the same catchments while runoff accumulated across the Thessalian plain and around Lake Karla.
Event timeline
- 4 Sep — Persistent rain begins across eastern and central Greece.
- 5–6 Sep — The heaviest rain affects Magnesia, Pelion and Thessaly. Copernicus EMS is activated.
- 7 Sep onward — Runoff continues towards the plain and Lake Karla, prolonging the flood conditions.
What happened in the atmosphere
A cut-off low remained almost stationary over the eastern Mediterranean. The warm sea continuously supplied moisture, while low-level convergence and the terrain of Pelion enhanced uplift.
The event shows why a rainfall total is not enough on its own. Duration, hourly intensity, soil saturation, catchment shape and river discharge jointly determine the flood response.
What helps us interpret the event
- Compare hourly and multi-day precipitation, not only daily totals.
- Follow river discharge and satellite-derived flood extent together.
- Grid-based global analyses need comparison with local observations.
Historical analysis must not be used as guidance for a new event. During active severe weather, follow HNMS, Civil Protection, 112 and local authorities.