Another low-tech solution for dealing with a severe whiteout is to throw something ahead of you that is highly visible. This generally takes the form of a small, brightly colored stuff-sack (filled with snow or similar) attached to the end of ~5--10m of brightly colored cord or thin rope. Throwing the stuff-sack in the direction you wish to head and following cord, reeling it in as you go, can give you something to focus on and help distinguish the ground against blowing snow and fog, along with hopefully giving some indication that you might be approaching the edge of a cornice or open crevasse.
Attaching your end of the cord to a ski/trekking pole can enable a "bull whipping" or "fly casting" type motion to keep advancing your stuff-sack and make the process slightly less tedious.
This is certainly a technique of last resort and only provides help for micro-terrain navigation, but is easily fashioned with things you will always have along in the mountains.