What is this shit? America explain.
Half of your continent is mountains?
Is that even accurate?
I lived on the Colorado plateau for a while. Travelling around you don't really notice the elevation of 4 whole states being 3,000 ft above sea level (at its lowest point) because the change in elevation is very gradual. Clouds out there just feel a bit lower.
About 100 million years ago that whole mountain range was a shallow transcontinental sea that bisected Noth America (Gondwanna at the time) in half. One day it just started rising out of the ocean due to plate activity and it hasn't stopped since. The funny thing is that the much smaller Appalachian mountains are 10 times older.