The Caldor fire is very serious because it is so close to larger communities of people than most other fires

If you look on a map, to the west of the fire is Placerville, Pollock Pines, Sommerset, and on the eastern side, Kirkwood, Markleeville and all Lake Tahoe destinations. So, this whole area is full of houses and businesses. So, the Caldor fire is a real disaster in the making because of where it is located. 

Before this, the Dixie Fire is in a much less populated area.  It's true that Greenville was completely wiped out by the fire one day but most larger communities have been able to be saved even though many houses and buildings have burned in the Dixie fire.