(Portland, OR)  --  The search is ongoing for a hiker who's gotten lost above Horsetail Falls.  The Multnomah County Sheriff's Office says volunteer search organizations will join with deputies this morning in the effort to locate 33-year-old Jessica Wheeler of Wasco.  Wheeler was reported lost around 6:40 yesterday evening.  She set out on her hiking trip Monday with her dog.  Crews are reported to be heading toward Nesmith Point this morning.