Firefighters battled the debris to save dozens of people trapped in their homes as storms battered the scenic lake, popular with tourists.
An elderly woman stranded in her house was brought to safety, along with a disabled person and a caregiver isolated by a landslide.
No fatalities or injuries were reported.
About 50 residents were trapped in their homes when a landslide caused a gas leak in the most affected town, Brienno, located on the western shore of the lake.
Further south in Cernobbio, a building threatened with flooding was evacuated by firefighters.
Agriculture lobby group Coldiretti says extreme weather conditions have intensified in recent years, citing more frequent, sudden and severe storms, as well as short, intense rainfall and rapid changes from sunny skies to storms.
“We are facing in Italy the consequences of climate change, with a tendency to tropicalization and the multiplication of extreme events”, declared the group.
The group estimates that there has been € 14 billion (£ 12 billion) in damage over the past decade to agricultural production, buildings and infrastructure due to climate change events such as floods and landslides.
The extreme weather conditions on Lake Como come just a day after tennis ball-sized hailstones damaged nearly 100 cars and disrupted traffic on a main road near Bologna in northern Italy.
Images showed cars with windshields smashed by hailstones shot to the side of the road as drivers exited to see the damage.
Hailstorms are common in summer in the Po Valley in Italy.
But the strength and frequency of hailstorms this year have made the phenomenon “unusual”, according to meteorologist Luca Lombroso.
Analysis shows that hailstorms are occurring at the rate of 11 a day this summer, Coldiretti said, and 386 have occurred so far this year – a big increase from 92 in 2018 and 198 in 2019.
Until six years ago, only a few dozen hailstorms occurred each year.
“The size of hailstones has also changed, increasing dramatically in recent years with real blocks of ice falling from the sky – even bigger than tennis balls,” the group said.
Hailstorms can wipe out entire fields or vegetable and fruit orchards, and Coldiretti attributes a 40% drop in peach and apricot harvests and a 50% drop in nectarines to “this crazy climate.”