Episode 4, 24 December 1958
Analysis
Description
Meteorological background
On 17 December, pronounced pressure gradients developed as an upper-level ridge extended from NW Africa to the eastern Mediterranean, leading to increased surface pressure and strong S and SW winds over the Adriatic. On 18 December, the upper-level ridge shifted further to the east over the Mediterranean, while a short-wave trough moved over the Adriatic. Simultaneously, an intense Atlantic cyclone deepened to 960 hPa, creating strong air-pressure gradients across Europe. On 23 December, the influence of a northern anticyclone over the Adriatic weakened as a surface cyclone from the western Mediterranean approached. A SE wind began that evening, intensifying by day’s end. On 24 December, the cyclone’s center moved over the Adriatic, with winds shifting to strong SW, then W, before weakening on 25 December as the cyclone gradually dissipated.
Sea-level evolution
On 24 December 1958, at 05:00 UTC, the sea level in Bakar reached 93 cm above the long-term average. This maximum occurred during the daily tidal peak, which contributed 25 cm. Basin-wide oscillations were observed for much of the period leading up to the flood, with the final reinforcement occurring on 18 December. However, these oscillations largely dissipated by the time of the flood, which was primarily driven by a storm surge. Synoptic component contributed 27 cm to the total sea level during the episode.
The remaining sea-level rise resulted from processes acting on other time scales (refer to Figure 1 in the Introduction for detailed explanations). Local processes were negative (-2 cm), long-period sea-level variability added 28 cm, and mean sea-level changes contributed 15 cm.
In summary, the flood was driven by the constructive interaction of all involved processes, excluding local processes. While synoptic component was not particularly dominant, strong preconditioning combined with the daily tidal maximum played a significant role in amplifying the episode.
Newspaper reports
Here is an excerpt from report about the flood from Novi list.
UNUSUAL FLOODING IN TROGIR
The sea flooded the streets in the lower part of the town
TROGIR – For two nights in a row, the inhabitants of Trogir had to take measures to protect their homes from flooding. The high tide, which came in several waves over the past two days and nights due to the Sirocco wind, has raised the sea level so much that it has covered almost all areas of Trogir, except for the streets in the center. Since many taverns and other first-floor establishments are located below the normal level, the sea entered these premises and there was a risk that the food that was near the ground would be destroyed or the furniture damaged. In particular, various domestic animals in the stables were in great danger. The most vulnerable were the houses in PaÅ”ike, whose residents spent the whole night carrying away the water that had already entered. Many roads were impassable for a while and the sea came out of the canal. The inhabitants of Äiovo could not get into the town in the early hours of the morning because the access road was under the sea. For the same reason and because of the strong current in the sea, two fishing boats from Arabania were washed ashore.
