Bukasov admits that they have overestimated his 5-year-old daughter's abilities twice but stopped as soon as they realized she was struggling. One of those time was during a trip up Mount Elbrus in Russia, when Yunona battled subzero temperatures and cold wind.
"In both cases we stopped climbing probably well before her breaking point," Bukasov said.
Their trek up Mount Elbrus taught them that "[Yunona] is still not a match for high cold wind and sub-zero temperature, but also that she survives high altitude about the same as an adult climber with the same experience," Bukasov claimed.
After her long hikes, Yunona bounces back very quickly and is ready for the next day's adventures, he said. The extent of her symptoms from long hikes is mild headaches and low appetite, according to her father. Both of these effects are common for hikers of any age at high elevations.
Bukasov, who has been hiking for years, said that through his travels he has met many hikers along the way that have pointed out to Yunona's unique abilities.
"Hikers will stop her along the way, and say 'how old are you? I wish my boys would do that,'" said Bukasov. "Some peoples take pictures of us along the way to show their families."
"I started searching on the Internet for the youngest climbers on great mountains," said Bukasov. "When we found out those children are probably grossly underrepresented, underdeveloped and perhaps over protected, we decided to do as much as we can and as reasonably safely as we can to correct this."
Yunona enjoys hiking, her father said. "Some very hard hikes she might cry once or twice, like when it gets dark… 95 percent of the time or more she loves it," said Bukasov.
Yunona plans to climb Mount Kilimanjaro in Tanzania next year, which has a summit of about 19,500 feet.
Recine, who has attempted to climb Mount Kilimanjaro, believes that as long as you properly prepare for long hikes, the safety risks go down tremendously.
"There are always safety issues of climbing," said Recine. "I don't know much about Mount Whitney, but Kilimanjaro is not a technical climb. It's not easy, but you just walk up it which is fairly safe."
"From the standpoint of bones and joints it wouldn't be a terrible risk because of her age," said Recine. "As a matter of fact, at the older end of the spectrum, the risk is greater."