Räntäsateitä

Räntäsateitä, often translated as sleet or freezing rain, is a form of precipitation characterized by ice pellets. These pellets are formed when raindrops fall through a sub-freezing layer of air close to the ground. As the raindrops descend, they freeze into small, translucent balls of ice. Unlike snow, which forms as ice crystals in colder temperatures throughout the atmosphere, räntäsateitä originates as liquid water that solidifies upon contact with the cold air layer.

The accumulation of räntäsateitä can create slippery and hazardous conditions. The ice pellets can coat roads, sidewalks, and other surfaces, significantly reducing traction. This can lead to dangerous driving conditions, with increased risk of accidents. In meteorological terms, räntäsateitä is distinct from freezing drizzle, which consists of supercooled water droplets that freeze on contact with surfaces, forming a glaze of ice. Räntäsateitä, on the other hand, involves solid ice pellets that fall from the atmosphere.

The formation of räntäsateitä typically requires a specific atmospheric temperature profile: a layer of warm air above a layer of sub-freezing air near the surface. This inversion allows precipitation to fall as rain in the upper atmosphere before freezing as it passes through the colder layer. The size of the ice pellets can vary, but they are generally smaller than hailstones. Understanding the conditions that lead to räntäsateitä is important for weather forecasting and public safety advisories.