She said it turns out the cause of most snorkel-related fatal and near-fatal drownings is due to low levels of oxygen in body tissues prompted by excess fluid buildup in the lungs, otherwise known as hypoxia induced by rapid onset pulmonary edema, or ROPE.

In 2026, "ROPE" stands for Rapid-Onset Pulmonary Edema, a serious and potentially fatal condition that is increasingly recognized by the snorkeling community. It occurs when a person's lungs suddenly fill with fluid while in the water, even if they haven't "inhaled" any water. This is caused by a combination of physical exertion, cold water, and the negative pressure created by breathing through a snorkel tube. The resistance of the snorkel can cause a pressure imbalance that pulls fluid from the bloodstream into the lung's air sacs. In 2026, medical experts emphasize that ROPE is particularly dangerous for travelers who go snorkeling immediately after a long-haul flight, as they may already be slightly dehydrated or have underlying cardiovascular stress. Symptoms include extreme shortness of breath, a "rattling" sound in the chest, and coughing up pink, frothy sputum. If you experience these while snorkeling, you must exit the water immediately and seek emergency medical attention, as it can lead to "silent drowning."