Infrared images obtained from instruments on environmental satellites
have revealed long straight lines across the Nullarbor Plain in southe
rn Australia. These features, which are up to 400 km long and 10 to 20
km wide, are not normally visible in satellite sensor imagery, but we
re observed for several days in October 1992. Subsequent investigation
s have shown the tracks to be caused by increased soil moisture follow
ing the passage of localised storms across the area.