  We present an analysis of results on absorption from Ca II, Ca I, K I, and
the molecules CH+, CH, C2, and CN that probes gas interacting with the
supernova remnant IC443. The eleven directions sample material across the
visible nebula and beyond its eastern edge. Most of the neutral material,
including the diatomic molecules, is associated with the ambient cloud detected
via H I and CO emission. Analysis of excitation and chemistry yields gas
densities that are typical of diffuse molecular gas. The low density gas probed
by Ca II extends over a large range in velocities, from -120 to +80 km/s in the
most extreme cases. This gas is distributed among several velocity components,
unlike the situation for the shocked molecular clumps, whose emission occurs
over much the same range but as very broad features. The extent of the
high-velocity absorption suggests a shock velocity of 100 km/s for the
expanding nebula.
