Storm Agnes is the name given to a powerful mid-latitude storm system that brought very strong winds and heavy rain to Ireland and the UK in late September 2023, causing travel disruption, power outages, and localised flooding.

What is Storm Agnes?

  • Storm Agnes was the first named storm of the 2023–24 autumn/winter storm season for Ireland and the UK.
  • It was a deep Atlantic low-pressure system that rapidly intensified (a “bomb cyclone”) before hitting parts of Ireland, Scotland, Wales and northern England.
  • National meteorological agencies named it “Agnes” under the joint UK–Ireland–Netherlands storm naming scheme, used when strong winds or heavy rain are expected to cause significant impacts.

What did it do?

  • Brought gusts widely over 60 mph inland, with some exposed coasts seeing around 70–80 mph winds, leading to fallen trees and structural damage in places.
  • Caused yellow weather warnings for wind and rain, with forecasters warning of “difficult driving conditions”, possible power cuts, and disruption to road, rail, and ferry services.
  • Impacted mainly Irish Sea coasts (parts of Northern Ireland, Wales, northwest England) and then Scotland as it tracked northeast across the region.

Is it a hurricane?

  • No – although news can mention “hurricane‑force winds”, Storm Agnes was not a tropical hurricane but an extratropical (mid‑latitude) storm powered by large temperature contrasts, not warm ocean cores.
  • The name “Agnes” has also been used for a historic 1972 Atlantic hurricane (Hurricane Agnes), which caused catastrophic flooding in the eastern United States, but that is a different storm event with the same name.

Mini timeline

  1. Rapid deepening over the North Atlantic as it approached Ireland and the UK, undergoing “explosive cyclogenesis”.
  1. Landfall/peak impacts around 27 September 2023, with strongest winds around Irish Sea coasts and heavy rain over parts of Scotland and northern England.
  1. The system moved away into the North Sea and weakened after bringing a period of disruptive weather and prompting travel and safety warnings.

In short, when people ask “what is Storm Agnes?”, they are usually referring to the named Atlantic storm that hit Ireland and the UK in late September 2023 with damaging winds and heavy rain, not to a generic type of storm.

Information gathered from public forums or data available on the internet and portrayed here.