Storm Event

High tides and gales cause flooding and coastal damage

Severity ? 3

Source

The ‘Braer’ storm developed over Nova Scotia, Canada on 8th January 1993 and moved east towards the UK. On 9th January, the storm approached Ireland and combined with, and was enhanced by, another low-pressure system located southwest of Iceland. On 11th January, the storm moved north of Scotland, where the central pressure dropped to a record-breaking 914 mbar (Met Office, 2011). In the northern North Sea, the storm slowed down and moved back on itself before dissipating. The highest wind speeds of 106 knots [55 m/s] were recorded on an ocean weather ship located southeast to the storm centre. In Shetland, wind speeds of up to 83 knots [43 m/s] were recorded (Met Office, 2011).

The storm generated a skew surge of over 0.5 m at 32 of the tide gauge sites. Water levels exceeded the 1 in 5 year return level at 13 sites in the Irish Sea around Scotland and along the central south coast of England. This event was unique in that the 1 in 5 year return level was exceeded 24 times across these 13 sites, with multiple high waters exceeding this threshold at 7 sites. At Lerwick, 4 high waters (3 in succession) exceeded the 1 in 5 year threshold; this was because the storm remained almost stationary north of this site for nearly two days. The highest return period water level was at Lerwick and was 1 in 89 years. The second largest water level return period at Lerwick occurred on the previous high water and this had a return period of 1 in 78 years. The next largest return period of 1 in 32 years was at Wick. The highest skew surge was at Millport and was 1.03 m.

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

Pathway

We are unaware of any specific information concerning the flood pathways during this event.

Receptor and Consequence

During 10th–11th January 1993, many locations along the UK south and west coasts were flooded during this event (Eden, 2008; Ruocco et al. 2011; Odell and Parkes, 2013). “Mountainuous” seas hit Old Portsmouth, where flood water reached 3 ft. [0.9 m] deep in places. In Titchfield, the overflowing river caused reportedly the worst flooding ever known, with an equivalent description of the conditions in Selsey. Residential properties were flooded in Portchester, Fareham, Wallington, Ryde, Cowes, and Wootton Bridge. Many roads were reportedly impassable in and around Fareham, and the A27 was closed nearby Portchester. Serious flooding and one death (of a canoeist) was reported in the Strathclyde Region of Scotland (Met Office, 2011). On the English south coast, in the city of Portsmouth during 10th January 1993 severe flooding was reported in Broad Street (of the Old Portsmouth area) (PCC, 2008; Pomeroy, 2012). The prolonged duration of this storm was associated with flooding on 13th January (possibly continuing from the previous days) on the Isle of Wight (Newport,) and Fareham (Portchester, Warsash and Wallington; Ruocco et al. 2011). Several local roads and some quayside property was inundated.

References

  1. Met Office, 2011. Sunday 10 January 1993 (The Braer Storm), Available at: http://www.metoffice.gov.uk/media/pdf/8/7/Braer_Storm_-_10_January_1993.pdf.
  2. Eden, P., 2008. Great British Weather Disasters, London: Continuum UK.
  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. Odell, L. & Parkes, B., 2013. The Braer storm Revisited. Weather, 99, pp.1–8. Available at: https://www.researchgate.net/publication/236842916_The_Braer_storm_Revisited
  5. PCC, 2008. Flooding in Portsmouth; list of flood incidents. Unpublished email/report provided by Portsmouth City Council to M. Wadey
  6. Pomeroy, S., 2012. Pomeroy’s of Portsmouth (Britain’s Island City) – Weather and Natural Phenomena [Online]. Website on local history by Stephen Pomeroy, Available at: http://homepage.ntlworld.com/stephen.pomeroy/local/weather.pdf