1 ES-82, Space Sciences Laboratory, NASA Marshall Space Flight Center, Huntsville, AL 35812

2 Department of Physics, University of Alabama, Huntsville, AL 35899

The spectral evolution of observed flares' hard X-ray emission is found to conform to certain patterns in color-color diagrams (CCDs). By combining the spectral resolution of BATSE data with the spatial resolution of HXT data, we are able to address the nature of flare energy release and anticipate what kind of observations HESSI may make of the energy release/particle acceleration site in flares. The implications of these observations for theoretical models of acceleration and propagation are considered.