  The depth-dependence of bubble concentration at pressures above the
transition to the air hydrate phase and the optical scattering length due to
bubbles in deep ice at the South Pole are modeled using diffusion-growth data
from the laboratory, taking into account the dependence of age and temperature
on depth in the ice. The model fits the available data on bubbles in cores from
Vostok and Byrd and on scattering length in deep ice at the South Pole. It
explains why bubbles and air hydrate crystals co-exist in deep ice over a range
of depths as great as 800 m and predicts that at depths below $\rm \sim$ 1400 m
the AMANDA neutrino observatory at the South Pole will operate unimpaired by
light scattering from bubbles.
