DeSoto County, MS has run out of Democratic ballots in some precincts and is low everywhere. It's not clear what this means even if turnout is particularly heavy, and the county officials didn't merely severely underestimate turnout.
While DeSoto County is one of the less heavily African-American counties in Mississippi (18.8% compared to 37.1% statewide), that doesn't necessarily mean that this unexpectedly heavy turnout means significantly more white voters (which would generally be perceived as helping Senator Clinton).
See, DeSoto County is suburban Memphis. And it has had a skyrocketing population. After hitting a high of 32,021 residents in 1870, it declined to 23,891 by 1960. Since then, though, it's grown heavily as people have fled Memphis for the suburbs, by about 50% every ten years.
From 2000-2006, the Census Bureau estimates DeSoto county gained about 37,000 residents, growing from 107,199 to 144,706, and one expects this growth has continued .
However, this most recent growth has differed. Most of the past growth was the white flight that's occurred around the country. However, starting from 1990-2000, African-Americans began fleeing the city as well. During this decade, the white population grew 33090 while the black population grew just 3541 (as well as about 1,000 residents of some "other race" [likely Latino]). While reducing the black percentage of the population from 12.8% to 11.8%, it likely marked the first significant growth in black population in generations.
Since 2000, however, black growth has skyrocketed, with more new black residents than white residents. As of 2006, the Census Bureau estimated DeSoto was 18.8% black; today, it may be 20% black.
If it's this growth that has accounted for the huge increase in Democratic ballots [and it's likely that it is], then this should help Obama out.
We'll see in a few hours, I guess.