  The propagation of fronts in the Fisher-Kolmogorov equation with spatially
varying diffusion coefficients is studied. Using coordinate changes, WKB
approximations, and multiple scales analysis, we provide an analytic framework
that describes propagation of the front up to the minimum of the diffusion
coefficient. We also present results showing the behavior of the front after it
passes the minimum. In each case, we show that standard traveling coordinate
frames do not properly describe front propagation. Lastly, we provide numerical
simulations to support our analysis and to show, that around the minimum, the
motion of the front is arrested on asymptotically significant timescales.
