28 October 2011
The remarkable rainfall that caused the floods and landslides in Italy this week
Posted by Dave Petley
Summary: Rainfall records from Liguria this week suggest that peak rainfall intensities were truly exceptional – at one gauge they exceeded 140 mm per hour – leading to the flood and landslide disaster that affected northern Italy on Tuesday.
A couple of days ago I highlighted that northern Italy had suffered very heavy rainfall, inducing floods and landslides in particular in the Liguria and Tuscany regions. Data on the rainfall at Brugnato in La Spezia, one of the worst affected areas, has been made available via the meteonetwork.it site:
http://forum.meteonetwork.it/meteorologia/138511-grave-alluvione-lampo-nel-levante-ligure.html
This is an extraordinary volume of rainfall, with total volume exceeding 500 mm and hourly intensities of more than 50 mm for five hours. The maximum hourly intensity of over 140 mm is rarely seen outside of a tropical cyclone. It is no wonder that the consequences were so serious.
The www.cittadellaspezia.com website has detailed coverage of the event (in Italian of course), including a gallery of images collected on the day:
http://www.cittadellaspezia.com/fotogallery/Alluvioni-e-frane-Le-immagini-del-561_1.aspx
http://www.cittadellaspezia.com/fotogallery/Monterosso-le-foto-dell-apocalisse-564_1.aspx
The final death toll in this disaster is not known at present.
Dave Petley is the Vice-Chancellor of the University of Hull in the United Kingdom. His blog provides commentary and analysis of landslide events occurring worldwide, including the landslides themselves, latest research, and conferences and meetings.
in few hours, very heavvy
Philip Eden indicated such events were likely to happen along the Ligurian coastline on his regular Radio 5-Live commentary on Monday night
Yes, this area is very prone to high rainfall rate. Italian record rainfall in 24 hours was set around Genova in the 1970 flood: more than 900 mm.
very interesting data (like in India dam failure?). do you have maximun in 1 hour.
this data confirm the influence of human activity more than climate
I tried to search for 1 hour max rainfall but couldn’t find it. I post a very impressive video about water and mud flow during the floods: very scary, it gives you an impression about the energy of water: http://www.youreporter.it/video_Alluvione_Vernazza_auto_e_furgoni_risucchiati.
On the web is possible to see some pictures recently tacken after the disaster around the Vernazza village: http://www.facebook.com/media/set/?set=a.2184514252703.2109136.1242397367&type=3 . Apart from the huge landslide visible by the sea (last pictures) it is in my opinion incredible the failure of so many terraces (which i guess are fairly old and seems to be well mantained). Dave, aren’t terraces very stable usually?