(Beaverton, OR)  --  Police in Washington County are searching for a missing and endangered teenage girl.  The Washington County Sheriff's Office says 16-year-old Emmeline Tesch went missing just before noon Friday near Ridgewood View Park in Beaverton.  Police say she was last seen getting off a MAX train at the Oregon Zoo stop.  Officials say she's "medically fragile and in grave danger."  Anyone with information is urged to contact police.