Review of the Tsunami Evacuation 2017

Executive Summary
This report has been prepared as a result of the tsunami evacuation along the Christchurch City
coastline on 14 November 2016, following a 7.8 magnitude earthquake on land near Culverden,
Canterbury. The residents of Christchurch and Christchurch City Councillors raised various queries
following the evacuation. Predominantly, the queries focused on why messaging appeared
inconsistent between agencies, how the evacuation decision-making process works, how evacuation
of coastal communities can be better coordinated, what information communities require and how
they can access such information.
It was determined (in early December 2016) that a review of the tsunami evacuation would best
provide responses to these queries and identify any issues. The review was undertaken by way of
interviews (with the Mayor of Christchurch City, internal Council staff and external parties), workshops
with the Community Boards in coastal areas, subject matter research and written correspondence
with various parties. Some delays have occurred as a result of the Port Hills Fire and the challenges to
gain time for interviews. It was also decided that both the Ministry of Civil Defence & Emergency
Management (MCDEM) and the regional Canterbury Civil Defence Emergency Management (CDEM)
Group referred to as “Group” should be invited to provide feedback on the draft report.
The conclusions drawn can be summarised as follows:
1. Christchurch Civil Defence Emergency Management (CDEM) tried to gather as much
information as quickly as possible regarding the tsunami risk specific to Christchurch, to
determine whether to activate an evacuation. Overall, the CDEM team did its best. There are,
however, areas of improvement which should be implemented.
2. Whilst CDEM received all the national warning messages issued by the MCDEM, the messaging
across agencies and media was inconsistent. The media reported the tsunami warning and
recommendation that people evacuate from ‘low-lying areas’ before a national warning
message was issued by MCDEM to the local civil defence groups confirming that a “land
threat” was present.
3. The sirens were not activated in Christchurch until the national warning message issued by
MCDEM at 2:01am made it clear that the tsunami threat was not only to marine and beach
areas but included land. The national warning message issued by MCDEM was followed by a
telephone direction from MCDEM to Group that an evacuation of Christchurch coastal
residents was necessary. MCDEM has advised that they do not recommend the use of tsunami
sirens for local source tsunamis, especially those that do not have voice capability.
4. Although it is not clear how many residents actually evacuated before the tsunami sirens were
activated, most Christchurch coastal residents relied on the sirens to signal an evacuation was
required.
5. The Christchurch Police’s evacuation plan for coastal areas has been in place for over 10 years,
but as an operational document, there is no public knowledge of it. On 14 November, a
tsunami evacuation map was available on Council’s website 1 . Residents were not immediately
directed to the map; nor were they provided with a procedure to follow in order to evacuate.
Many residents were unclear whether they needed to evacuate or not and where the
evacuation zones started and finished.
6. Residents want clear, concise, consistent messaging across all agencies in all forms of media
including letterbox drops, social media, internet, seminars, and information on noticeboards in
1
http://www.ccc.govt.nz/services/civil-defence/what-to-do-in-an-emergency/tsunami/distant-source-tsunami/
4