I live in St Louis, on the edge of what is considered north county. Ferguson is about 5 miles north of my little burg. I grew up close to that area and know the area of Ferguson, Dellwood, Jennings and Florissant quite well. In fact, my two childhood homes are quite close to streets that have been mentioned in the news a lot- Chambers and West Florissant. If you take those roads towards the edge of St Louis County from Ferguson you'd pass through the neighborhoods where I spent most of my years until I was 19 and got my own place. I know that area well.
I'm not surprised by the racial tension, that's an area that has been in transition my whole life. Section by section black people have moved in and white people have moved out to either west St Louis County or adjacent St Charles county. Hell, my family was one of those- we moved from Bellefountaine Neighbors to lily white (at the time) Florissant when my dad noticed the first black family on our street. When my mom moved from that house in Florissant a couple years ago that neighborhood was occupied by black folks in majority numbers. Anytime you get one demographic displacing another there is going to be more tension. I've heard it mentioned that St Louis is one of the most segregated urban areas in the nation.