  Thermal leptogenesis is an attractive mechanism for generating the baryon
asymmetry of the Universe. However, in supersymmetric models, the parameter
space is severely restricted by the gravitino bound on the reheat temperature
$T_{RH}$. For hierarchical light neutrino masses, it is shown that thermal
leptogenesis {\it can} work when $T_{RH} \sim 10^{9} $ GeV. The low-energy
observable consequences of this scenario are $ BR(\tau \to \ell \gamma) \sim
10^{-8} - 10^{-9} $. For higher $T_{RH}$, thermal leptogenesis works in a
larger area of parameter space, whose observable consequences are more
ambiguous. A parametrisation of the seesaw in terms of weak-scale inputs is
used, so the results are independent of the texture chosen for the GUT-scale
Yukawa matrices.
