RHYL's coastal defences were overtopped by very large waves, driven onshore by gale force winds during high astronomical tides an atmospheric storm surge.
That is the finding of a report into the flooding which hit the Garford Road area of Rhyl last December.
It says secondary defences were breached at Garford Road, but would have been overtopped anyway due to the volume of water coming over the main sea wall.
The Natural Resources Wales Review into the floods states that the standard of protection at the Garford Road area of Rhyl should be identified and evaluated, including detailed hydraulic analysis of the capacity and performance of the storage lagoon, an assessment of the stairwell and slipway openings and the interaction with the adjacent golf course area.
Denbighshire Council has undertaken a topographical survey of Rhyl Golf Course to determine the capacity of the course to temporarily store water which overtops the defences, before releasing it back out to sea at low tide.
A report said: "The initial feasibility assessment is favourable.
"However, discussions with Rhyl Golf Club will be required before detailed proposals can be finalised.
"Specialist consultants have been appointed to assist with the hydraulic analysis of the lagoon and the golf course. The consultants will also look at options to reduce the risk of overtopping of the primary coastal defences between Splash Point and the Golf Course."