On a blog devoted to life and death issues, this really does not fit in, but here it is anyway. When you buy snack chips, there is air in the bag. This helps prevent the chips from being crushed. It also means that snack chips must be packaged for the altitude where they will be sold. Chips packaged in Denver, CO and sold at sea level will be flat and the air inside the bag will not protect them. Chips packaged in Phoenix, AZ (about 1100 feet) expand to make each bag look like a pillow.
We picked up a load of snack chips in Lubbock, TX headed to Vancouver, WA, just across the river from Portland, OR. The most important instruction was follow their routing to keep the bags from exploding. Lubbock, TX is approximately 3200 feet, so that gives us a little more altitude than chips packaged at sea level. We safely crossed NM (7200 feet @ Cline’s Corners), Cortez, CO (6200 ft) and Price Canyon, UT (approx 7700 feet).
Our personal chips have often exploded, when we used different routes. We attempt to stay on interstates, so these are not the highest roads possible. Some bags have popped at Homestake Pass, Montana 6393 feet. Bags that are still intact will usually pop on I80 @ Happy Jack Road in Wyoming; 15 miles east of Laramie, Wyoming (8665 feet). But if that still does not work, I70 across Colorado will finish off anything that has not popped yet. At 11,192 the Eisenhower Tunnel, about 75 miles west of Denver, is the highest point anywhere on the US interstate highway system.
Not all bags pop the same way. Usually the bottom pops with just a little poof and the contents are fine. But we had a bag of cheese curls pop around 10,000 feet that were mostly cheese powder. That taught us that loud bangs turn the contents to powder. Enjoy the remains.