  Ice-coated dust grains provide the main reservoir of volatiles that play an
important role in planet formation processes and may become incorporated into
planetary atmospheres. However, due to observational challenges, the ice
abundance distribution in protoplanetary disks is not well constrained. We
present JWST/MIRI observations of the edge-on disk HH 48 NE carried out as part
of the IRS program Ice Age. We detect CO$_2$, NH$_3$, H$_2$O and tentatively
CH$_4$ and NH$_4^+$. Radiative transfer models suggest that ice absorption
features are produced predominantly in the 50-100 au region of the disk. The
CO$_2$ feature at 15 micron probes a region closer to the midplane (z/r =
0.1-0.15) than the corresponding feature at 4.3 micron (z/r = 0.2-0.6), but all
observations trace regions significantly above the midplane reservoirs where we
expect the bulk of the ice mass to be located. Ices must reach a high scale
height (z/r ~ 0.6; corresponding to modeled dust extinction Av ~ 0.1), in order
to be consistent with the observed vertical distribution of the peak ice
optical depths. The weakness of the CO$_2$ feature at 15 micron relative to the
4.3 micron feature and the red emission wing of the 4.3 micron CO$_2$ feature
are both consistent with ices being located at high elevation in the disk. The
retrieved NH$_3$ abundance and the upper limit on the CH$_3$OH abundance
relative to H$_2$O are significantly lower than those in the interstellar
medium (ISM), but consistent with cometary observations. Full wavelength
coverage is required to properly study the abundance distribution of ices in
disks. To explain the presence of ices at high disk altitudes, we propose two
possible scenarios: a disk wind that entrains sufficient amounts of dust, thus
blocking part of the stellar UV radiation, or vertical mixing that cycles
enough ices into the upper disk layers to balance ice photodesorption.
