  Using Raman spectroscopy, we investigate the lattice phonons, magnetic
excitations, and magneto-elastic coupling in the distorted triangular-lattice
Heisenberg antiferromagnet alpha-SrCr2O4, which develops helical magnetic order
below 43 K. Temperature dependent phonon spectra are compared to predictions
from density functional theory calculations which allows us to assign the
observed modes and identify weak effects arising from coupled lattice and
magnetic degrees of freedom. Raman scattering associated with two-magnon
excitations is observed at 20 meV and 40 meV. These energies are in general
agreement with our ab-initio calculations of exchange interactions and earlier
theoretical predictions of the two-magnon Raman response of triangular-lattice
antiferromagnets. The temperature dependence of the two-magnon excitations
indicates that spin correlations persist well above the N\'eel temperature.
