urstromtal UK /ˈʊəstɹəʊmˌtɑːl/US /ˈʊɹstɹoʊmˌtɑl/ noun1 •A broad glacial valley formed during an ice age by meltwater flowing roughly parallel to the ice margin.On the southern margin the plateau falls to a sandy outwash plain which merges into the zone of urstromtäler. — 1950 formsurstromtals · urstromtäler