Storm Event

Coastal flooding to properties across the Solent, Sussex, and southwest region

Severity ? 3

Source

The storm developed southeast of Nova Scotia, Canada on 19th November 1984 and moved northeastwards towards the UK. On 20th November, the storm combined with, and was enhanced by, another low-pressure system located west of Newfoundland, Canada. Central pressure dropped rapidly to below 960 mbar. The storm crossed to the north of Scotland on 24th November and dissipated to the north of Norway on 25th November. The storm generated strong southwesterly winds over the British Isles. The maximum recorded wind speeds on 23rd November were 70 knots [36 m/s] at Herstmonceux, Sussex, 74 knots [38 m/s] at Glenna Head, Cornwall and 73 knots [37 m/s] at Guernsey Airport, Channel Islands (Met Office, 1984).

The storm generated a skew surge of between 0.25 and 1.0 m at several sites in the Bristol Channel and Irish Sea and between 0.25 m and 0.75 m along the east coast of the UK. Water levels exceeded the 1 in 5 year return level at two sites, Lerwick and Aberdeen. The return period water level was 9 years at both sites. The corresponding skew surges were 0.38 m and 0.41 m respectively. The event occurred at peak spring tides.

We are unaware of any sources describing the wave conditions during this event.

Pathway

Other than reports of a breach in defences at Hayling Island, we are unaware of any further specific information regarding the flood pathways during this event.

Receptor and Consequence

This event saw reportedly the worst flooding in living memory at Shoreham, Sussex where 34 residential properties and an entire factory were flooded, beach huts were destroyed and one road and several gardens were inundated (BBC, 1986). This event was also associated with flooding in many locations around the Solent, Hampshire (Ruocco et al. 2011). A breach in defences at Hayling Island flooded local roads, property and a car park. Considerable flooding exacerbated by heavy rainfall was also experienced in areas of Portsmouth. Other impacted areas included Southampton, Lymington, Fawley, Fareham, Cowes, and Ryde. There was widespread disruption to traffic and businesses, and damages to property.  Flooding also occurred along parts of the north Devon coastline (Hansard, 1984). One newspaper article described the impacts at Sandy Point, Hayling Island where many residential properties were flooded during this event with “freak” conditions which occur once in 250 years (Ruocco et al. 2011). Other impacted areas included Langstone, Ryde and Cowes, with the high street in the last location flooded to a depth of 3 ft. [0.9 m].

Cornwall Council (2011) also noted an event of unspecified time in November 1984; associated with “major” flooding in Fowey and Padstow (12 and 35 properties inundated, respectively) due to a combination of high sea levels and high river flows, with reportedly less serious flooding in Wadebridge, Sladesbridge and Perranporth. Whilst the day in the information source is unspecified, we can establish that these occurrences are very likely to be part of this event as the only extreme sea level that month was on the afternoon of 23rd November, so is assumed to be this event which also affected locations further east on the English south coast.

References

  1. Met Office, 1984. Monthly Weather Report of the Meteorological Office. Monthly Weather Report. Available at: http://www.metoffice.gov.uk/learning/library/archive-hidden-treasures/monthly-weather-report-1980
  2. BBC, 1986. Domesday Reloaded: Flooding on Shoreham Beach. Available at: http://www.bbc.co.uk/history/domesday/dblock/GB-520000-102000/page/1 [Accessed March 27, 2015].
  3. Ruocco, A.C. et al. 2011. Reconstructing coastal flood occurrence combining sea level and media sources: a case study of the Solent, UK since 1935. Natural Hazards, 59(3), pp.1773–1796. Available at: http://link.springer.com/10.1007/s11069-011-9868-7 [Accessed March 27, 2015].
  4. Hansard, 1984. South-West England (Flood Warning), Available at: http://hansard.millbanksystems.com/written_answers/1984/nov/30/south-west-england-flood-warning [Accessed September 29, 2015]
  5. Cornwall Council, 2011. Preliminary Flood Risk Assessment ANNEX 5 – Chronology of Major Flood Events in Cornwall, Truro.