The deluge generated a raging torrent in the hills above which was funneled down the surrounding valleys directly into the settlement, busy with tourists and villagers.
By the time it hit the streets, it had generated enough momentum to smash inside homes and businesses, wash away cars and fell huge trees.
HM Coastguard played its part that day in the rescue response alongside the rest of the emergency services and local residents.
Villagers and tourists stranded by the flooding were helped by Boscastle’s own Coastguard Rescue Team as well as those from Port Isaac, Bude, Polzeath and St Austell.
Airlifts were carried out by a fleet of seven military and HM Coastguard helicopters, in partnership with RNLI lifeboats from Port Isaac, Bude and Padstow, plus police, fire and ambulance services.
Members of the public joined the rescue operation too, pulling people from stranded cars and helping them to higher ground.
The joint effort by the community and its emergency services prevented any loss of life that day – although £2m of infrastructure damage was caused and 60 properties were flooded.
It was an event that will live long in the memories of local people, said James Instance, who is now HM Coastguard Divisional Commander based at Falmouth but who was then Watch Manager.
He witnessed the wreckage first-hand when he came on shift the next day, and recalls the reports from Coastguard Rescue Officers at the scene.
James said: “What started as a fine morning for Boscastle, with villagers and tourists going about their business, turned into a scene of devastation with pictures broadcast all around the world.
“Anyone who was part of that day will never forget the power of the water or the bravery and collaboration between the public and emergency services, including HM Coastguard, who worked together to ensure everyone was saved.
“To have seven helicopters and excellent co-operation from all the blue lights on scene was a great example of the UK emergency services at their best.”