Cat III can be done with no DH, but you still require some RVR>0 (flare is done by the autoland system). Only IIIc could be done in theory with a blocked windsc

Cat III can be done with no DH, but you still require some RVR>0 (flare is done by the autoland system). Only IIIc could be done in theory with a blocked windscreen like in this case, but that's still not in standard operation anywhere that I know of.