Traveling to higher altitudes or over mountains after diving can increase a diver’s risk for DCS. In this scenario, the diver already has increased partial pressures of nitrogen in his tissues from diving. Traveling to higher altitudes reduces the ambient pressure further, potentially causing the surface tension of the gas in solution to exceed the tolerable limits, which would ultimately result in the formation of bubbles.
The table by side will help calculate the group a diver should be in prior to traveling to higher altitudes in order to prevent bubble formation.