Helicopters with infrared technology have joined the search for a Kiwi paraglider missing in the United States.
James "Kiwi" Oroc (Johnston) was reported missing in Nevada on Saturday, local time, while paragliding southwest of Eureka County.
He lifted off from the Shoshone Mountain, near Round Mountain in Nevada and planned to fly to Wendover, a Nye County Sheriff's Office (NCSO) spokesman said.
Oroc was flying with two other pilots, who raised the alarm after 24 hours of no contact with them, he said.
An extensive search and rescue operation has been under way since Sunday, with searchers scouring the terrain by foot and air.
Oroc's GPS tracker showed he was last recorded at about 14,500 feet (4419.6 metres) in the Ninemile Peak area at 2.14pm on Saturday.
By then, Oroc had been flying for around three hours and had covered 86km.
He'd planned to cover another 114km before the end of the day.
A journalist, photographer and artist, Oroc regularly flew long distances: in November 2018 he broke his previous New Zealand overseas open distance record by flying 384km in Quixada, North Brazil.
The previous record - 316km - was also held by Oroc.
On Sunday, the two pilots flying with Oroc searched roads along Oroc's likely course-line, as NCSO staff searched the area around Oroc's last logged coordinate in the northern end of Nye County, near Ninemile Peak.
"Ninemile Peak area has an altitude ranging from 8800 feet to 10,000 consisting of rugged forest terrain," the NCSO spokesman said.
The next day, NCSO staff teamed up with Eureka County Sheriff's Office's search and rescue team to ramp up the search.
Additional land and air resources, including helicopters equipped with infrared technology have been added to the search as it continues.
A number of commercial pilots and paragliders had joined in search efforts, with three aircraft in the skies just hours into the search.
"The circumstances and condition of Johnston are unknown at this time," the NCSO spokesman said.
"The search is ongoing."
In a statement, the Johnston family thanked everyone involved in the ongoing search efforts.
"Our brother is courageous, loyal and loving and has so many friends around the world that have reached out in support, both emotionally and financially," the statement read.
"We have also appreciated the assistance from NZ Mfat for reaching out to authorities in the US for help with specialised resources."
A GoFundMe page, set up to fund further search efforts for the well-known pilot has raised more than $122,894 (US$81,421) in donations.
With an elevation of 3055m, Ninemile Peak is the highest point in Nevada's Antelope Range, according to mountaineering community website Summitpost.
Rescuers were working on the theory that Oroc's Garmin InReach was in freefall when it sent its last trackpoint, as its ground speed was just 3.9km/h - too slow for thermalling or reserve drift given the wind, the page said.
The search crew were working on the assumption that if Oroc had thrown his reserve at altitude, he would have drifted downwind, northeast of his last known position and so are focusing search efforts there.
Originally from New Zealand, Oroc lived in Jackson Hole and more recently New Orleans, while making regular flying trips, the page said.
A Ministry of Foreign Affairs and Trade spokeswoman said the search for Oroc was being co-ordinated by the Nye County Sheriff's Office, Nevada.
Mfat was in contact with Oroc's family and local authorities, she said.
No further comment would be provided due to privacy reasons.
Since 1998 Oroc has "pursued and reported on the cutting edge of extreme sports" in more than 40 countries around the world, his website says.
Oroc's work has appeared in magazines, films, and on MTV Sports.
A regular contributor to Cross Country magazine, Oroc had 30 years of experience as a pilot, the magazine shared online.
"We hope he'll be walking out with one hell of a story."
But time was of the essence in the search and recovery efforts, with fires in the area hampering visibility and storms forecasted to hit, the post said.
Oroc assisted search efforts of another paraglider reported missing in Peru in 2011.
He reported on the experience of searching for his missing friend, Xavier Murillo, for Cross Country magazine.
A member of the Burning Man community since 1999, Oroc is also involved in the documentation and advancement of "Alternative Culture", publishing three books on the use of psychedelics.