At what elevation is it unlikely for HAPE to occur?

High-Altitude Pulmonary Edema (HAPE) is a serious condition that can affect individuals who ascend to high elevations too quickly without proper acclimatization. The risk of HAPE significantly increases as one ascends to elevations above approximately 8,000 feet, reaching its most critical levels above 12,000 feet.

At elevations below 11,000 feet, while HAPE is still possible, it is much less common, and individuals typically begin to show early symptoms before deterioration into severe conditions. Elevations around 12,000 feet and above are where HAPE becomes a more prevalent risk, especially in individuals who are not acclimatized or who ascend rapidly. Therefore, stating that HAPE is unlikely to occur at 11,000 feet reflects that that altitude is on the cusp of higher risks but not yet at a level where severe symptoms are commonly expected to manifest. Thus, 11,000 feet is often considered a threshold where the likelihood for HAPE starts to become a concern, while elevations notably higher present a much more immediate danger.