Plasma formation on the surface of thick aluminium metal, in response to a pulsed multi-megagauss magnetic field, is experimentally investigated. The dynamics of the pulsed aluminum rod and resultant surface plasma are examined with time-resolved imaging, pyrometry, spectroscopy, and laser shadowgraphy; and time gated EUV spectroscopy is used characterised the emission lines from multiply ionised aluminium atoms. The measurement of the time-evolution of the surface temperature, aluminum expansion rate, and ionization state, as a function of applied field, significantly constrains the choice of models used in radiation-magnetohydrodynamic simulations.