In the early hours of the 7th of January 1928, flood water broke over the banks of the Thames, destroying homes and drowning 14 people.
20-year-old Madge Franckeiss had been sleeping in a basement flat at Hurlingham Court Mansions.
Despite escaping, she repeatedly swam back inside to save her 15-year-old brother, then his friend Billy Watson and Billy’s mother.
The ceremony will take place on Tuesday at noon, with performances from Madge’s descendants and St John’s Walham Green primary school.