Fire Evacuees?

Maybe someone can explain something to me:

I get that the folks who are staying at the Charger's stadium are being treated a lot different than those who were in the Superdome during Hurricane Katrina. Some government officials are capable of learning lessons.

What I don't understand is this: Why is it that the people who have been forced to leave their homes during the SoCal fires are being called "evacuees" and those who were forced to leave their homes during Hurricanes Katrina and Rita were called "refugees?"