(This is fan speculation. This is no way canon and a way to explain my white furred treecat)
A white treecat is an oddity on Sphinx these days.
At one point this was not the case.
the Copperwall Mountains has mant mountains, and is home to many clans, at one point, before humans ever arrived with ther boomstick, there was another Clan.
upon the highest mountain, snow constantly coated the ground, bleaching the rocks and what few trees live there white. The clan name has long been forgotten or told as mere legend among other clans.
However, the regular gray/cream or brown was a disadvantage here, so over time, the fur of this clan turned white, blending in with the year round snow.
during a particularly bad winter, an avalanche was triggered by an Earthquake from a few miles away. The snow buried the cave the clan used as their nest and an ice storm locked most the treecats inside for longer than the food stores lasted, the snow may have also caused the cave to collaspe.
A few treecats were out hunting or visiting other clans, after they were unable to save their clan mates they joined other clans.
They got their own mates, but white in green forests is a very bad disadvantage. Even with the 'cats intelligence, Condor Owls, hexapumas and other predators were able to easily pick off white tree kittens who stray too far from the nest.
This was not the end of the white fur gene however, kittens of the same litter who turned out the normal colors carried the gene into later generations, every once in a lucky while a white treecat was born, though most would not survive long. only one or two ever reached breeding age before picked off for their white fur.
SnowFire's clan was one of the more reclusive clans. When she was born, she was protected with the upmost care, but she didn't appreciate it. Her Treecat name is Flame of the Snow and her personality was just like fire. very hard to tame. Unlike most of her dead kin, she lived past the first breeding season and soon became curious about humans. She longed to see them, as the clan always sent her away when the rangers visited.
So in Defiance of her elders, she struck out for a human city, finding her way gradually to Tillingham. Many people were stunned, a a white treecat had never been seen before.
as Flame of the Snow made her way through a public park she suddenly felt something. She turned to look at a short human and the bond between them formed immediately. Flame jumped right into Caitlyn StarNight's arms, knocking her to the ground. StarNight couldn't speak for a good half hour, before she named Flame of the Snow SnowFire, testifying to how close their bond is.