Hope you're enjoying your time in Florence!
I just found an article on La Nazione from today giving us an idea of what's on the program to commemorate the 55th anniversary of the flood. Tommorow at 5pm there is a book presentation in Palazzo Vecchio, while the main events will be definitely be on the 4th: at 11.15am there is a mass in the basilica of Santa Croce. At 12 noon after the mass there will some several speeches by local officials, while at 12.45pm at the Ponte alle Grazie bridge a ceremony forsees the launch into the Arno of a bay leaf wreath in memory of the lives lost during the flood. Lastly, on Saturday November 6th, at 5pm in Palazzo Vecchio, a presentation of another book.
I think because of covid there aren't too many things going on, in the past there have been photo and video exhibits to show the effects of the flood and how the city is working to create a system that should take care of any future risks of flooding from the Arno.