In order to operate the power grid aggressively enough to make full use of renewable power, operators need new tools for situational awareness and control.  Phasor measurement units (PMUs) have been developed for the past thirty years, but first saw wide-scale production grade deployments in the US after DOE investments funded by the American Recovery and Reinvestment Act of 2009.  PMUs report voltage and current phasors thirty or more times every second, promising operators a real-time picture of the state of the grid -- but only with systems and algorithms that transmit the data and analyze this information at similar rates. In this talk, we describe fast analysis using PMU-sensed “fingerprints" of different types of system events (e.g. changes in line status or reconfiguration of substations).  Our system, FLiER (Fingerprint Linear Estimation Routine) identifies system changes in close to real time through a novel filtering operation that lets us discard most potential events from consideration with little computation. We describe the elements of our approach, as well as giving an overview of work in progress to improve the quality of our results (and the range of contingencies we can handle) by monitoring the frequency content of transient "ringing" as the system passes from one state to another.