LJ Idol Presents:

I think it's definitely possible to lengthen what you have. You've kept the entry pretty bare-bones in spots, there are areas where you could put more descriptions, maybe more inner thoughts from Rafaela. I'm not sure if you'd consider that "padding" or not, but if it relevant to the story - and to letting your readers know more about Rafaela - then I think it is wordage well spent.

A few critique points:
...fifteen-year-old Rafaela Torres shivered on a sandbar in the frigid air of the earliest hours of November, her flannel pajamas and salt-and-pepper pixie haircut soaked by the West Fork White River of Washington County, Arkansas.

When the wraith had swept past her tent, she could have let it go. Of course she couldn't. Follow it, she thought. I've never seen a wraith before, she thought. It'll be fun, she thought.

a) Maybe it's just me, but the term "salt-n-pepper" makes me think of older people. I know her hair is black-and-white, but for me at least that isn't quite the same as salt-n-pepper. I'm not sure if the coloration is artificial or natural, but you might consider using different terminology.

b) If she's never seen a wraith before, and if - as you state a little further down - wraiths are invisible, how did she sense its presence and know to follow it? If it was some sort of feeling (the whole "like someone walking across your grave") describe it / her reaction to it.

"Roy," whispered the man in green, "they always said the bridge was haunted, but--"
The cooler slammed into his stomach.
"Joe!" cried the one in red whose name was Roy.

I know this is supposed to be humorous, but the Roy-Joe-Roy thing strikes me oddly. Maybe add a little detail beyond their names and that they are wearing green and red? Perhaps height (ie: "the taller man in the green jacket"), facial hair, etc?

"Why didn't you help me?" she whined. "I could have drowned! Or squished to death!" –I think this should read "or been squished..."

I’d also like some description of her father, both in a physical sense and also more action from him - all he really does is clap and wipe away a tear.

You've got a good start with this. Good luck with submitting it!