The system emerged into the North Atlantic and underwent explosive cyclogenesis; the first severe weather warnings were issued for the United Kingdom and Ireland on 4 February well in advance of the storm's arrival.

The precursor low named Winter Storm Kade by The Weather Channel brought heavy snowfall to the northern United States and eastern Canada, especially Newfoundland, New England and New York; further south in the Mid-Atlantic and Southeastern U.S., flooding and tornadoes were reported.

[2] The worst effects from Ciara were felt in Ireland and the United Kingdom, where the storm arrived over the weekend of 8–9 February, bringing high winds and heavy rainfall that caused severe damage, widespread flooding, and three fatalities in the latter country.

On 4 February, the Met Office issued a yellow warning for wind for the following weekend for a potential storm, covering all of the United Kingdom.

The storm was formally named Ciara by the Met Office in the United Kingdom,[5] Sabine by the Deutscher Wetterdienst in Germany,[6] and Elsa by the Norwegian Meteorological Institute in Norway.

[8] The precursor system further developed over the northeastern United States, bringing 80 mph (130 km/h) wind gusts to coastal New England on 7 February.

[10] 9,000 customers lost power in the Oklahoma City metropolitan area, where several school districts, colleges and universities closed due to the inclement weather.

[18] On 4 February, the Met Office issued a yellow warning for wind for the following weekend for a potential storm, covering all of the United Kingdom.

[21] The severe warning, which was later withdrawn, was issued for the River Nidd at Pateley Bridge where a water level of 5.1 m (17 ft) was expected to pose a "danger to life" and overtop flood defences.

[20] High winds created by Storm Ciara over the United Kingdom and the North Atlantic meant that a British Airways Boeing 747-400 with the registration G-CIVP[22] broke the record for the fastest subsonic flight between John F. Kennedy International Airport in New York City and London Heathrow.

The aircraft was propelled by a strong tailwind and the jet stream across the Atlantic Ocean, completing the journey in 4 hours and 56 minutes.

[23] Alongside two Virgin Atlantic flights which arrived around the same time, it surpassed the previous world record of 5 hours and 13 minutes, set by a Norwegian 787 Dreamliner in January 2018.

[24][25] In Hawick, Scottish Borders, part of a guest house and cafe collapsed into the River Teviot, leaving some rooms exposed.

[26] On 10 February, a 58-year-old man from Micheldever, Hampshire, died after a tree fell on his car during the storm, where wind speeds were estimated to be in excess of 60 mph (97 km/h).

[35][36] Severe gales on 9 February led to fallen trees in Smeale, Braddan and Colby, and a power outage in the Andreas area.

[43] Many soccer matches including the 2020 President of Ireland's Cup, Gaelic Athletic Association (GAA) games and racing were postponed or cancelled due to the arrival of Ciara.

[62] On 10 February, the unusually low pressure from the storm led to multiple flight cancellations, as some aircraft were unable to compensate their altimeters.

[65] On 10 February, sea level along the Swedish west coast were the highest in 34 years, in some areas as high as 137 cm (54 in) above average.

Roads and parking lots were flooded and ferries were cancelled due to too high water level at their docking stations.