They've been giving evacuation warnings for many days with both leaflets and the cell phone network:
> Residents in Gaza reported that Israeli planes rained red leaflets on neighborhoods Saturday, urging residents to evacuate. Those with cell phones also received the message digitally, according to social media reports.
> Residents in Gaza reported that Israeli planes rained red leaflets on neighborhoods Saturday, urging residents to evacuate. Those with cell phones also received the message digitally, according to social media reports.
https://www.politico.com/news/2023/10/21/idf-prepares-for-gr...