There is no way to know in advance how much time you will have to evacuate. In an ideal world, you would have many hours to prepare, but it is not uncommon to have only a few minutes' warning. The time you will have depends on the fire behavior, which is driven by wind speed, amount of fuel (vegetation), and topography, along with the proximity of the fire to your house. Fire and police try to order the evacuation with enough time to provide a buffer of safety, but this is not always possible. As such, residents sometimes think they will have more time than they do and not take the evacuation seriously.