page_title: Hook echo
hierarchical_section_title: Hook echo
caption_attribution_description: A radar image of a violently tornadic classic supercell near Oklahoma City, Oklahoma, USA on 3 May 1999.
context_page_description: A hook echo is a hook shape seen on a weather radar of some supercell thunderstorms. It is produced by rain, hail, or even debris wrapping around the thunderstorm. A hook echo is a sign that a tornado has formed or is forming. If a hook echo is seen on radar, the National Weather Service may issue a tornado warning.
context_section_description: A hook echo is a hook shape seen on a weather radar of some supercell thunderstorms. It is produced by rain, hail, or even debris wrapping around the thunderstorm. A hook echo is a sign that a tornado has formed or is forming. If a hook echo is seen on radar, the National Weather Service may issue a tornado warning.
caption: A hook echo on the radar image of the May 3, 1999 supercell thunderstorm that produced an F5 tornado in Moore, Oklahoma.