my wife has been an avid skier and snow boarder her whole life.
she lived in denver for a while.
She has been to brianhead multiple times.
I got altitude sickness a few times 20 years ago at mammoth but never anywhere else and never since.
i never saw her impacted at altitude at all.
She has been to brian head multiple times including last year.. with no issues.
We had already been skiing pretty high up a few times this year.
Mammoth and big bear.
but.. I agree it could have been the flu plus altitude.
however, I can also tell you..
my daughter had it before brian head.
she and many of her class mates were out with flu like systems.
her friends and her cousins went to the hospital with the flu.
a few went more than once.
they all tested negative for the flu.
by the way... friends of hers had just been to china over christmas.
our thesis is her schools was exposed right after christmas.
just a working thesis... no guarantee.
Dude. Brian's Head is 9800 ft MSL.
Most people who are *visiting* that altitude are going to feel bad after about a week. My friends and family gather at a ski resort each year and the same ones get sick every year. Some get headaches but others get a bad cold. Its genetic. After years and years of it I know which ones to keep an eye on.
There used to be a facility on a mountaintop outside of Quito, Ecuador supporting the Deep Space Network and we would send people there... and they would drop dead. It kept happening for years until someone figured out it was altitude sickness. Then they required engineers to stay in Quito for 2 weeks before they went up to stay at the site and they stopped dying.
I used to be pretty unaffected by altitude. I've skied at 14,500 ft and had to climb up with gear the last 2000 feet. But now I feel it. In the winter I take a job at the local ski resort in exchange for a season pass and a locker and some other perks. Above 9000 I can literally feel shortness of breath, tightness in my chest and the need to stop occasionally.