The Effect of Altitude on Stoves

The higher you go, the lower the atmospheric pressure. This will affect your stove. With a cartridge stove, which is essentially gas held under pressure, the drop in external pressure causes the gas to bleed out more forcibly.

This has one advantage: assuming other negative variables such as cold temperature are removed, you can get a slightly better burn rate and a small increase in perceived performance over the life of the canister.

On the negative side, you can experience ‘blow out’, where the stove is difficult or impossible to ignite, ignites incompletely, or goes out mid-burn for no apparent reason. This is caused by either excessive gas pressure or a lack of available oxygen.

Blow outs are both frustrating and dangerous. A flame-out means gas is leaking into the surrounding air, which is toxic and potentially explosive if not dealt with quickly. On a committing climb there is also the nightmare scenario of losing large amounts of fuel, which in turn means less food and, more critically, less water if snow has to be melted.

As the pressure inside the cartridge drops, blow out should reduce or cease, but by that point you may already have lost a significant amount of gas.

Partial ignition or blow out can also be caused by insufficient oxygen reaching the flame. This is a common problem with hanging stoves whose ventilation is designed more for sea-level use. The solution is to improve airflow to the flame and increase the combustion area, specifically the distance between the flame and the pan.

This issue is usually confined to hanging stoves and may require lifting the pan supports or drilling additional ventilation holes.