  We report on the highly extinguished afterglow of GRB 070306 and the
properties of the host galaxy. An optical afterglow was not detected at the
location of the burst, but in near-infrared a doubling in brightness during the
first night and later power-law decay in the K band provided a clear detection
of the afterglow. The host galaxy is relatively bright, R ~ 22.8. An optical
low resolution spectrum revealed a largely featureless host galaxy continuum
with a single emission line. Higher resolution follow-up spectroscopy shows
this emission to be resolved and consisting of two peaks separated by 7 AA,
suggesting it to be [O II] at a redshift of z = 1.49594 +- 0.00006. The
infrared color H-K = 2 directly reveals significant reddening. By modeling the
optical/X-ray spectral energy distribution at t = 1.38 days with an
extinguished synchrotron spectrum, we derive A_V = 5.5 +- 0.6 mag. This is
among the largest values ever measured for a GRB afterglow and visual
extinctions exceeding unity are rare. The importance of early NIR observations
is obvious and may soon provide a clearer view into the once elusive 'dark
bursts'.
