Cape Town - A mini tsunami may be the reason for the sudden rise and fall of the sea level along the West Coast over the last few days.
The National Sea Rescue Institute (NSRI) received reports that the sea level in Hout Bay, St Helena Bay, Saldanha Bay and Lambert's Bay changed suddenly three times on Thursday.
In Hout Bay, the water level first fell by a metre and then rose again by the same amount in the space of 20 minutes.
Factories were damaged by the high waves in St Helena Bay.
The NSRI called in the help of Geoff Brundrit, a retired professor of the University of Cape Town's Oceanography Department, to help investigate the phenomenon.