( CNN ) -- On Sunday night , two teenagers called authorities pleading for help after their hike through the Santa Ana Mountains of southern California went awry . Then their cell phones went dead -- meaning that not only were they lost , but so , too , was their link to potential saviors . Their story took a positive turn Wednesday night , when rescuers came across 19-year-old Nicholas Cendoya . But there was no sign of his hiking mate , 18-year-old Kyndall Jack . Until now . Video shot Thursday from helicopters showed Jack perched precariously on a steep area full of dense brush . A rescuer was by her side , and she was hoisted up to an awaiting helicopter and transported to a local hospital . `` She is alive , '' Orange County Sheriff 's Lt. Jason Park said . Park did n't offer much more than that as he addressed reporters Thursday . He said the teenage girl was `` responsive , ... she appears to be dehydrated , she 's weak . '' But the fact she survived four days in the wilderness was cause for celebration . Park described her family as `` extremely happy '' upon hearing about her rescue . There was similar elation among the search-and-rescue team , which included dozens of volunteer sheriff deputies who surveyed the dangerous terrain looking for signs of life . `` Regardless of how hard they worked or how how tired or how hungry they are , it 's a tremendous victory for them , '' Park said . The ordeal began on Easter , when the two teens set off on trails in part of the Cleveland National Forest located in an unincorporated part of south Orange County . The pair called the sheriff 's department that night , and deputies responded , believing the hikers were about a mile from their vehicle . `` But their cell phone battery died , and contact was lost , '' the department said in a news release . That set off a frenetic search through an area marked by dense brush and steep terrain . A big break came Wednesday night , when Cendoya was discovered , but his hiking mate was nowhere in sight . `` He believed they had been separated possibly since Sunday night and has no recall how they got separated , '' searcher Michael Boyle told reporters . Cendoya is being treated at Mission Hospital in Mission Viejo , where Dr. Mike Ritter said he is `` awake and talking . '' `` Nick wanted me to convey to all of you ... how grateful he is for all the help , '' Ritter told reporters . As to Jack , Mike Leum with the Los Angeles County Sheriff 's Department said he heard her before he saw her Thursday . `` So I was screaming , yelling across the canyon , 'Can you see me ? ' '' Leum recalled . `` 'Yes I see you , ' ( she responded ) , and I could not see her yet , because she was on top of a rock behind a bush . '' Leum said he asked Jack to wave the one arm she could , at which point he finally spotted her . By then , a helicopter was on its way -- from which a paramedic at one point descended to check on Jack , and into which she ascended on her way eventually to a nearby hospital . `` She was in a lot of pain , obviously completely dehydrated , and very weak and going in and out of consciousness , '' said Jim Moss , also with the L.A. County Sheriff 's Department . `` We just told her not to move because she was in a pretty precarious place . '' During Jack 's rescue , an Orange County volunteer deputy sheriff `` sustained head trauma '' after falling 60 feet , the sheriff 's department lieutenant said . The volunteer was in serious but not life-threatening condition at Mission Hospital -- `` able to move his arms and his legs ... and he is alert , '' said Orange County Sheriff 's Lt. Erin Giudice . Orange County Fire Authority Capt . John Muir said one lesson from the ordeal -- even with the happy ending -- is that hikers should plan first and plan for the worst . `` If you 're going to go hiking , we want you to be safe , we want you to prepare , '' he said .
NEW : Rescuer says Kyndall Jack , Wednesday , yelled out to him before he finally spotted her . NEW : She was dehydrated , in pain and `` going in and out of consciousness '' She is found in southern south Orange County 's Kyndall Jack , having set off for an Easter hike . Her hiking companion was rescued alive 18 that night .