A knowledge gap exists between what emergency responders know from their direct experience and what emergency planners know from analysis and reflection. The theory of practical drift suggests that shared understanding between planners and responders may break down as local response practice adapts and evolves with respect to static planning knowledge. Here we discuss how practical drift impacts emergency preparedness and, using Sch?n?s theory of reflective practice, describe how design of collaborative technology might help mitigate this knowledge disparity. We draw on two field studies, one national, and one at the local level, to illustrate dimensions of the problem space.