Ever heard of frazil ice? If not, you're not alone! However, for those who love the great outdoors, especially avid hikers, understanding a bit about this peculiar form of ice and its potential dangers can be crucial.
Frazil ice often goes unnoticed despite its appearance – resembling a mix of snow and ice or slushy snow. On a closer look, it manifests as tiny particles, typically around 1mm or smaller, often taking the shape of thin disks or forming slushy circles known as pancake ice, particularly in windy and rough sea conditions.
The term "frazil" finds its roots in the French word fraisil, translating to cinder.
So, how does frazil ice come into existence? Turbulence in water plays a pivotal role, occurring when the water becomes "supercooled" as surface water loses heat to the cold air above, requiring the water temperature to be just below freezing.
According to the Yosemite National Park's Facebook page, frazil ice occurs when fast-moving, turbulent water gets so cold that it resembles a slushie but poses a more perilous threat than a delicious treat.
Scientifically, as explained by the Iowa Institute of Hydraulic Research, frazil ice forms in flowing or turbulent water that becomes supercooled due to heat transfer to the overlying air. The intensity of turbulence and the rate of temperature drop in the water determine the amount and size of ice particles formed.
Frazil ice tends to grow rapidly once initiated. As reported by the Treatment Plant Operator magazine, it first forms, then multiplies, and eventually attaches to underwater structures like water system intakes.
Where might you come across frazil ice? This phenomenon is exclusive to cold weather and requires clear, cold nights with some wind to induce water turbulence. It can appear in rivers, lakes, reservoirs, and oceans. Frazil ice is more likely to be observed in regions with extreme winters, such as Canada, the US, Antarctica, and the Baltic Sea.
But why is frazil ice so treacherous? Described by Professor Brian Morse as "a snowstorm in water," frazil ice accumulates rapidly and can be deceptive in appearance. It may look like patches of snow or slushy river water, but underneath, it is solid and swiftly forming.
For outdoor enthusiasts, especially winter hikers, the danger lies in the risk of falling through frazil ice into extremely cold water below. Yosemite National Park rangers issued warnings to winter hikers, emphasizing that despite its mesmerizing appearance, frazil ice is not a solid surface. Its slushy exterior can hide the boundaries of secure footing, posing a serious hazard.
In areas vital for water supply, frazil ice can become a significant menace, forming blocks around water outflows and impeding water flow to homes, businesses, industries, and people. Navigating winter or frozen seas can also pose challenges for vessels due to the potential dangers of frazil ice.
So, while frazil ice may not be a household term, its presence and hazards are something outdoor enthusiasts, hikers, and those in vital water supply areas should be aware of, especially during colder seasons.
