Hail is a form of frozen precipitation, consisting of layered ice pellets that fall from storm clouds. While primarily composed of water, its formation process means it is not simply frozen distilled water. Hail’s creation involves sweeping up various materials present in the air. Therefore, the question of edibility raises health concerns related to both the physical nature of the ice and the contaminants it carries. Hail is markedly different from the ice found in a home freezer.
Immediate Physical Hazards of Hail Consumption
The most immediate dangers of eating hail relate to its extreme cold and its hard, layered structure. Unlike soft snow or crushed ice, hailstones are formed through the accretion of supercooled water droplets, creating a dense, opaque, and solid pellet. Attempting to chew a hailstone poses a risk of dental damage, including chipping or fracturing a tooth. The extreme hardness of the ice makes it comparable to biting down on a small stone.
The size of the hailstones also presents a localized choking hazard, particularly for small children. Even pea-sized hail can be swallowed improperly, and larger, irregular pieces increase the risk of mechanical obstruction. Additionally, the rapid introduction of intensely cold material can cause temporary, sharp pain in the mouth and throat, known as cold sensitivity. This exposure may also cause a mild, temporary “frostbite” sensation on the sensitive tissues of the tongue or cheeks.
Airborne Contaminants and Biological Risks
The atmospheric formation of hail is the primary mechanism for collecting a variety of harmful contaminants. Hailstones begin to form when water vapor freezes around tiny particles suspended in the air, known as ice nuclei. These nuclei are not always pure water molecules; they can be dust, soot, or other airborne pollutants that become the core of the growing hailstone.
The hailstones circulating within the storm cloud non-selectively collect whatever is present, including microorganisms like bacteria, fungal spores, and viruses. Research shows that hailstones contain high concentrations of dissolved organic carbon and total dissolved nitrogen, compounds that support the growth and survival of microbial populations. Some bacteria are categorized as ice-nucleating active (INA), meaning they actively facilitate the freezing process and are inherently part of the hail’s composition.
Chemical pollutants are another concern, as hail acts as a scavenger of the atmosphere. The ice incorporates industrial emissions, such as sulfur dioxide and nitrogen oxides, which are components of acid precipitation. Studies have detected various compounds, including nitrates, sometimes at concentrations beyond safe levels for drinking water. If the hail is collected after landing on the ground, a roof, or a car, it also picks up surface-level contaminants like dirt, bird droppings, and residual chemicals, drastically increasing the risk of consumption.
Assessing the Likelihood of Illness and Recommended Action
While hailstones contain a documented inventory of biological and chemical contaminants, the likelihood of severe illness from consuming a very small amount is generally low. However, the risk is not zero, and the amount of contamination depends highly on the local air quality and the size of the storm. Consumption introduces a small but unnecessary risk of ingesting pathogens that could cause gastrointestinal distress.
Therefore, it is recommended not to eat hail, especially for vulnerable populations like children. If a person experiences symptoms after eating hail, such as prolonged diarrhea, severe vomiting, or fever, they should seek medical attention. Mild, temporary stomach upset is a more likely outcome than a serious infection, but any persistent or severe symptoms warrant professional evaluation. The safest course of action is to treat hail like any other form of environmental precipitation.