A Revere High School graduate on a hiking excursion with friends in New Zealand is missing and presumed dead after extreme weather trapped the group without refuge.

Allison “Ally” Willen, 20, has been missing since last Friday in Mount Aspiring National Park. Her two companions were able to hike to safety and notify authorities.

New Zealand media reported that an initial land and aerial search uncovered several items of clothing and a backpack belonging to Willen near the high water mark of the Young River, a find that prompted searchers to believe she may have been swept away by the swollen water.

In a statement, Willen’s family said her father and uncle traveled to New Zealand on Tuesday to help search the remote countryside.

“All indications of the professional recovery effort are that the event was not survivable,” the family statement said.

Willen, who graduated from Revere in 2012, was attending Eckerd College in Tampa, Fla., where she was pursuing a degree in human development.

She was in New Zealand for a semester as part of an international studies program at the University of Otago in Dunedin.

Willen is the daughter of Todd and Michelle Willen of Bath Township.

Her family said she was an accomplished artist and photographer with a “vibrant and adventurous spirit, who filled her time with travel, as well as the many causes for which she was a devoted advocate.”

“We are devastated by the loss of our dear Ally,” the family statement said. “Although the grief that we are experiencing is great, we have been comforted by the outpouring of love and support from friends and an extended community of those who loved Ally. We thank everyone who has thought and prayed for us, and for Ally, at this extremely difficult time.”

A memorial service will be planned. In lieu of flowers or gifts, donations can be made to One of a Kind Pets or Girls on the Run, where she often volunteered.

According to New Zealand media, Willen became separated from her hiking party on the Gillespie Pass, between Young and Wilkin valleys.

Recovery efforts were suspended Wednesday because of high water levels.

“The search has been suspended for a few days to allow the river levels to recede as much as possible so that when we recommence on Friday or Saturday we have the very best chance of finding Ally for her family,” Wanaka land search and rescue police coordinator Aaron Nicholson told the Otago Daily Times.

Paula Schleis can be reached at 330-996-3741 or pschleis@thebeaconjournal.com. Follow her on Twitter at http://twitter.com/paulaschleis or on Facebook.