One of many wrenching scenes in Spike Lee’s documentary When the Levees Broke is a man bringing his mother back to the horrible ruin of her home. The man is Terence Blanchard, a trumpeter and band leader. He also wrote the music for Spike Lee’s film. Blanchard has just come out with a new album that expands on that score, and he talked to us about his experiences writing about Katrina. Produced by Reese Erlich.