It is another example of extreme weather phenomena that an agricultural lobby said had intensified in recent years.
In Brienno, on the lake's western shore and the hardest hit town, 50 residents were blocked in their home when a landslide caused a gas leak.
Further south in Cernobbio, firefighters evacuated a condominium threatened with flooding.
“We are facing in Italy the consequences of climate change, with a trend toward tropicalization and the multiplication of extreme events,” Coldiretti said, citing more frequent, sudden and violent storms, short and intense rainfalls and rapid changes from sunny skies to storms.
Coldiretti estimated 14 billion euros of damage over the last decade to agriculture production, buildings and infrastructure because of climate change-provoked events like flooding and landslides.
The storms devastating Lake Como come a day after hailstones the size of tennis balls damaged nearly 100 cars and stalled traffic on a highway near Bologna, in northern Italy.
Video showed cars with windshields shattered by the hailstones pulled over on the side of a highway as stunned drivers and passengers surveyed the damage.
While hailstorms are a common summer feature in Italy's Po River Valley, meteorologist Luca Lombroso told the Bologna daily, il Resto di Carlino, that the strength and frequency of hailstorms this year has made the phenomenon "unusual."
Coldiretti said its analysis shows that hailstorms are occurring at the rate of 11 a day this summer, with 386 recorded so far this year.
That compares with a few dozen a year up to six years ago, a rate that grew to 92 in 2018 and 198 in 2019.
“The dimension of the hailstones also has changed, growing considerably in the last years with real ice blocks falling from the sky — even bigger than tennis balls,” Coldiretti said.
Hailstorms can wipe out entire fields or orchards of vegetable and fruit. Coldiretti attributes a 40 per cent drop in peach and apricot harvests and a 50 per cent drop in nectarines to “this crazy climate”.
Additional reporting by the Associated Press.