To start with, I love disaster movies. I think Hollywood blockbusters have their place. I think some of the really bad ones that still entertain have their place. But I really love these well written, well acted, and more realistic films.
They take a premise that isn't likely but at the same time is not completely scientifically unsound as most Hollywood movies. They show a city that actually seems to have a plan for if they need to evacuate. People seem to be more reasonable about it. It isn't a case of people on one hand refusing to believe and everyone else in a complete and utter state of panic. It looks like someone really researched what a city like that might need to do in order to evacuate a significant portion. It shows real people dealing with their lives and suddenly having this added issue added to the issues they already have. Just enough drama to keep the story moving but this movie is really a combination of being plot and character driven rather than driven by special effects. It is low budget but despite that, I think the effect are surprising good for what they were trying to depict.
This movie is really worth watching and deserves a higher IMDB score than people have given it.