Yellowstone National Park officials launched an aerial search Sunday for 22-year-old Austin King, who mysteriously disappeared after leaving for a hike in bad weather.

Yellowstone’s public affairs office confirmed to Cowboy State Daily Friday that Superintendent Cam Sholly requested an “extensive” search because areas of the park previously under snow became visible in recent days.

Rescue efforts also continue on a personal level. King’s father, Brian King-Henke, is using a GoFundMe page to organize an independent search party for his missing son in the Wyoming wilderness.

The concerned father’s most recent update came to the webpage on Friday, when he informed the page’s followers that he had set up base camp at Eagle Creek Campground on the park’s Canadian border national.

“We have guys coming in today and tomorrow other teams will come out. Thank you all for everything,” King-Henke wrote Friday on the page.

King-Henke recently discovered during his research a strange note that his son had left at the top of the peak where his father last heard from him on September 17.

Park officials reported Oct. 2 that they had shifted their rescue efforts from search and “rescue” mode to “recovery” mode — a search for a suspected corpse.

“The park has continued limited search efforts since its reduction,” a Yellowstone spokesperson told Cowboy State Daily via email.

“We are aware that the father is attempting to coordinate additional search efforts for the coming days and have provided him with information on search efforts conducted to date,” the spokesperson said. “We are also warning all these additional searchers to be aware of the dangerous terrain and severe weather forecast for next week.”

Snow is expected again from Thursday in the national park.