A strong bad weather he hit particular on the area of Milan And in general on northern Italy yesterday 6 July, with intense storms, hail and strong wind that hit the vast areas of Lombardy. In the small town of the Milanese Robecchetto with Induno A 63 -year -old woman died crushed by a tree shot down by the fury of storm; With her a 70 -year -old man and a 68 -year -old woman were injured. Always in the Milanese the river Seveso It is essential despite the lamination tanks, causing inconvenience in transport. An Italo train was hit by lightning at Melegnano on the Milan-Rome high speed line, while multiple areas were flooded, in the Ponte Lambro district, mobile barriers and parks were positioned closed for safety reasons. There were also inconveniences in Piedmont, Liguria, Veneto, Emilia-Romagna and Friuli-Venezia Giulia and Tuscany. Strong phenomena of bad weather were widely foreseen, but many have remained surprised by the scope of the phenomenon, which was so intense because of the passage of a band of aligned temporals called Squall line.
Bad weather in Lombardy and storms in Milan: what is one Squall line and why it was formed
From a meteorological point of view, what happened yesterday in Lombardy goes under the name of Squall line (lines in Italian), or more technically Quasi-Linear Convective System (“Almost linear convective system”). As the name suggests, this is not a single thunderstorm but a long “Temporal band” aligned along a cold front. These structures, typical of the summer months, have lengths of over 100 km and widths of 20-50 km, can produce strong gusts of wind (in Milan the 80 km/h), even very intense rainfall (beyond 30 millimeters In Milan in a short period of time), also hail of considerable size and sometimes trumpets of air.
The Squall line They are formed when, especially during a heat wave, the very warm and humid air on the ground clashes with the cold air coming from a cold front. This cold air leads to the condensation of the water vapor in the distinct cumulonembo air (i.e. temporal schemes) are arranged along the line of the front following almost without continuity. In this case, the cold air came from Iceland, driven by a cyclonic vortex active in northern Europe that diverted cold currents through the United Kingdom and France to the point of bringing them to the Alps, where they gave rise to the cumulonembi who unloaded on the Po Valley and in particular on Lombardy.
Because there was no water bomb on Milan
Then there is an important thing to clarify: many titles speak of “water bomb in Milan”, but The water bombs do not exist. It is an exclusively journalistic term and not used in the meteorological field, in which the strong rainfall take the name of storms or at most, for exceptional events, violent storms.
It may seem like a semantic quibble, but calling things with their name, without using terms that suggest effects that do not present themselves in reality, it is important because helps prevention by the damage caused by extreme weather phenomena, which unfortunately are becoming increasingly frequent and increasingly intense due to global warming.
