(Woodland, WA)  --  Washington state transportation officials say one northbound lane of Interstate 5 near Woodland will be closed indefinitely.  Two lanes were reopened Thursday after space was cleared from a rock- and mudslide that covered the highway Wednesday.  WSDOT says keeping a single lane closed will keep traffic moving safely while the agency develops the next steps for stabilizing the hillside.  KGW-TV reports concrete barriers are in place to separate the two open lanes of northbound I-5 from the closed lane.