The flash floods that devastated west Attica, with 15 confirmed dead so far, were the third worst flooding disaster recorded in Attica in terms of the number of victims, experts told the Athens-Macedonian News Agency (ANA) on Thursday.
According to Dr. Kostas Lagouvardos of the National Observatory of Athens, where he is head of research at the Environment and Sustainable Growth Institute and in charge of its weather site meteo.gr, Wednesday’s flooding in west Attica was outstripped only by the major flood in Athens’ western suburbs on November 5-6, 1961 and that on November 2-3, 1977 in the same area.
Dr. Lagouvardos said meteo.gr scientists believe the rainfall on Wednesday must have been very localised, with most of the water falling on the mountains north of the affected area, though there was no weather station in the area that might confirm their estimates.
By analysing satellite images, however, scientists were able to discern a feedback phenomenon of the storms in the area between 3:00 and 7:00 on Wednesday morning. “This could cause continuous rainfall in a very restricted area, leading in this way to a sudden flood with the disastrous consequences that we saw,” Lagouvardos noted.
This was made more intense because the region had received a lot of rain on Monday and Tuesday, so that the soil was quickly saturated, he added.
Further evidence that the phenomena were very local came from weather station measurements in nearby Vilia, Elefsina and Agioi Theodoroi, which recorded only a few millimetres of rain.
Chief research Dimitra Founda, on her part, noted that rainy days in Athens and Attica were steadily decreasing but rains, when they did fall, were more intense. She said this was shown by an analysis of data on total annual rainfall in Athens in the National Observatory’s historic archives, going back to 1860.
“Even though rainfall shows strong variation from year to year, with periods of different trends for reduction or increase, it is clear that the long-term trend on the scale of a century and a half has remained almost stable,” she said.
This showed an increase in the number of days of strong of very strong rain in Athens per decade, with the biggest percentage of strong rains occurring between 1998-2007.