acronym for High Altitude Mega Fart. They can occur when living in or visiting high elevations. Known to happen during ski trips and hiking trips in the mountains and also on-board airplanes. Believed to be caused by the large difference in pressure between your insides and the low pressure of high altitudes thus causing a larger and more violent expulsion of gas through the anus than would occur at sea levels.
I need to get back home to sea level 'cause these HAMFs in Colorado are tearing a hole in my underwear.