The Fabric Science of a Mount Everest Expedition
At the Mount Everest summit, the wrong fabric can be fatal. Modern Mount Everest expedition clothing is a marvel of material science, designed to trap heat while allowing moisture to escape.
Base layers are almost always Merino. It stays warm even when wet and doesn't stink after days of Everest trekking. It is the natural choice for high-altitude endurance.
Your outer shell must be Gore-Tex or similar. It blocks the hurricane-force winds of the Everest summit while letting your sweat vapor out. Without it, you would freeze from your own moisture.
For the Death Zone, nothing beats a full-body down suit. It’s essentially a high-tech sleeping bag you can climb in. It is the iconic uniform of any successful Mount Everest expedition.
Don't compromise on your layers. Your clothing is your primary shield against the elements of the Mount Everest summit.