Well, she survived throughout the Twilight Saga. And in 'Breaking Dawn' she escapes with Jasper when she explains to the other Cullens' the presence of the Volturi in one month.
The Cullens' suspect she doesn't want to be killed, so she sorta bails out with Jasper. However, this is not the case. In reality, she travels to Chile where she gathers Nahuel; a vampire/human hybrid-like Renesmee Cullen. When Alice returns home to the Cullens' and their allies who face the Volturi, she explains that Nahuel is very old and a non-threat to vampires and that after 7 years of quick growth, he was an adult.
Once the Volturi leave, Alice explains to the Cullens' that she couldn't tell them so that Aro wouldn't know what she was doing.
In the end, Alice survived.