  High velocity gas that does not conform to Galactic rotation is observed
throughout the Galaxy's halo. One component of this gas, HI high velocity
clouds (HVCs), have attracted attention since their discovery in the 1960s and
remain controversial in terms of their origins, largely due to the lack of
reliable distance estimates. The recent discovery of enhanced magnetic fields
towards HVCs has encouraged us to explore their connection to cloud evolution,
kinematics, and survival as they fall through the magnetized Galactic halo. For
a reasonable model for the halo magnetic field, most infalling clouds see
transverse rather than radial field lines. We find that significant compression
(and thereby amplification) of the ambient magnetic field occurs in front of
the cloud and in the tail of material stripped from the cloud. The compressed
transverse field attenuates hydrodynamical instabilities. This delays cloud
destruction, though not indefinitely. The observed B-field compression is
related to the cloud's distance from the Galactic plane. As a result, the
observed rotation measure provides useful distance information on a cloud's
location.
