IJzel

Ijzel is a weather phenomenon characterized by a glaze of ice forming on surfaces when rain or drizzle freezes on contact with objects that are at or below 0°C. The result is a smooth, transparent ice layer that can cover roads, sidewalks, vegetation and other exposed surfaces.

Formation occurs when there is a layer of warm, moist air above the surface that produces liquid precipitation aloft as drizzle or freezing rain, while the air near the surface remains at or just below freezing. Supercooled droplets freeze instantly on contact with solid objects, creating icing. The thickness of the glaze depends on the rate of precipitation and the surface temperature.

Ijzel is most likely to occur when a warm air layer sits above a shallow cold layer near the ground, typically around 0°C. It can appear during late autumn, winter, or during thaw-freeze cycles and may be associated with fog. The phenomenon is more common in temperate climates, including coastal and inland areas, than in regions consistently below freezing.

The ice glaze poses several hazards. It greatly reduces traction on roads and pavements, increasing the risk of accidents. It can weigh down trees and power lines, causing branch or line failures and outages. In aviation, icing near airfields can affect aircraft performance and visibility, complicating takeoffs and landings.

Forecasting and terminology: In Dutch meteorology, ijzel is distinguished from snow and hail. Warnings may mention ijzel or icing potential when freezing drizzle or freezing rain is expected, and observers monitor reports from weather services and local media to assess ice accumulation.