Frazil ice is a type of ice that forms in cold water, typically in rivers or lakes, when the temperature drops below freezing. It appears as small, loose, needle-like crystals that float in the water, often creating a slushy texture. This phenomenon usually occurs in turbulent water, where the movement helps to break up the ice crystals. As frazil ice accumulates, it can clump together and form larger ice formations, which may lead to the development of anchor ice on the riverbed. This process can impact water flow and create hazards for navigation and aquatic life during winter months.