Description

Meteorological Background
In the week before the flood, a deep upper-level trough shifted from northern Europe to the Mediterranean, creating a strong southwesterly flow that brought warm, humid air and heavy precipitation to the Adriatic. This trough supported cyclonic activity in the western Mediterranean, generating a series of cyclones that crossed the Adriatic from the Ligurian Sea. Winds in the region were variable but predominantly southerly for extended periods. On 3 December at 00:00 UTC, the final cyclone in this series formed in the northern Adriatic and moved eastward. During the flood, light northwesterly winds prevailed in the northern Adriatic, while strong southerly winds affected the central part.

Sea-Level Evolution
On 3 December 2010 at 05:00 UTC, the sea level in Bakar rose to 91 cm above the long-term average. Tide was of semidiurnal spring-tide character and overall maximum occurred during the daily tidal peak. Therefore, tide contributed a significant 28 cm to the total sea level. The maximum sea level also coincided with a peak in synoptic component, heavily influenced by pre-existing seiches. Throughout the period, 21.5-hour oscillations dominated the residual sea levels, driven by a series of cyclones that had crossed the Adriatic before the flood. The final cyclone produced only weak winds and air pressure forcing in the northern Adriatic resulting in a modest storm surge. Hence, synoptic component contributed 26 cm to the total maximum, which was less than the contributions from tide and mean sea-level changes.
The remaining sea-level rise resulted from processes acting on other time scales (refer to Figure 1 in the Introduction for details): local processes were negligible during the episode (-1 cm), long-period sea-level variability contributed 9 cm, and mean sea-level changes added 21 cm.

In summary, the flood was caused by the combined effect of four processes, with synoptic component, tide, and mean sea-level changes contributing similarly.