21-04-2013 Hurricane Committee Learns Lessons from Sandy

The Hurricane Committee adopted a proposal from its Regional Specialized Meteorological Centre (RSMC) in Miami to broaden hurricane and tropical storm watch and warning definitions to allow these watches and warnings to remain in effect after a tropical cyclone becomes post-tropical, when such a storm poses a significant threat to life and property.

In future, the RSMC Miami will ensure a continuity of service by continuing to issue advisories during the post-tropical stage, when a storm poses a significant threat to life and property.

These changes were motivated by the special challenges posed by Hurricane Sandy, which evolved from a hurricane to a post-tropical cyclone prior to reaching the coast of the United States of America. They will be incorporated into the Operational Plan of the Hurricane Committee of WMO Regional Association IV (North and Central America and the Caribbean).

Special Session on Sandy

The committee met in Curacao 8-12 April to review the 2012 tropical cyclone season in the Atlantic and eastern North Pacific and prepare for the forthcoming season by strengthening warning services and regional coordination. It devoted a special session to Sandy, examining its occurrence in the Caribbean, impact on the USA, and aftermath in Canada through extra-tropical transition.

Sandy formed as a tropical depression on 22 October then strengthened as it crossed over the eastern portion of Jamaica on 24 October. It impacted on Haiti and made landfall in eastern Cuba as a Category 3 hurricane, with winds of up to 185 km/h (115 mph), with a storm surge reaching 2 meters (6.5 ft) high on the coast, with waves up to 9 meters (29.5 ft) high.

It weakened to a category 1 hurricane while moving through the central and north-western Bahamas but grew considerably in size. Sandy made landfall as a post-tropical cyclone near Atlantic City, New Jersey, with 130 km/h (80 mph) maximum sustained winds. Because of its tremendous size, however, Sandy drove a catastrophic storm surge into the New Jersey and New York coastlines.

Preliminary U.S. damage estimates are near $50 billion, making Sandy the second-costliest cyclone to hit the USA since 1900. There were at least 147 direct deaths recorded across the Atlantic basin due to Sandy, with 72 of these fatalities occurring in the mid-Atlantic and north-eastern United States. This is the greatest number of U.S. direct fatalities related to a tropical cyclone outside of the southern states since Hurricane Agnes in 1972.

Storm Surges

Most of the fatalities caused by Sandy in the USA were due to storm surge and most of the storm surge fatalities were those who were unable or unwilling to vacate their homes despite being ordered to evacuate. Post event reviews indicated that storm surge was not understood by the general public since they equated hurricanes with wind damage. To address the lack of understanding of the impacts of storm surge, the U.S. National Hurricane Center will produce storm surge warnings for the United States beginning in 2015.

The Hurricane Committee will discuss the coordination of all tropical cyclone related watches/warnings (including a storm surge warning) at its 2014 session.

Sandy replaced by Sara

The Hurricane Committee agreed to a request from the U.S. National Hurricane Center to retire the name Sandy from the official rotating list of Atlantic Basin tropical cyclone names. It will be replaced by Sara beginning in 2018.

Storm names are reused every six years for both the Atlantic and eastern North Pacific basins. If a storm is so deadly or costly that the future use of the name would be insensitive, the WMO hurricane committee retires the name. Sandy is the 77th name to be retired from the Atlantic list since 1954.

Other retired names include Irene (2011), Igor and Thomas 2010, Gustav, Ike and Paloma (2008) and Dennis, Katrina, Rita, Stan and Wilma (all 2005)

More details on tropical cyclone naming system

List of retired hurricane names since 1954

Bron WMO