A characteristic radar echo associated with some (but not all) tornadoes. It shows cyclonic curvature (and thus resembles the numeral ‘6’), and appears as an appendage to the larger echo returned by the parent multicell or supercell thunderstorm. It arises from backscattering from precipitation in a flow of air being drawn into a strong circulation, alongside a similar stream of precipitation-free air. Hook echoes may last just a few minutes and, although not infallible indicators of tornado development, do reveal extreme turbulence.
Subjects: Meteorology and Climatology.