'Mixed messages' over tsunami evacuation alert in Hawke's Bay
Questions have been raised in Napier over why the city's civil defence sirens were not activated despite the local civil defence team issuing a tsunami alert and telling people to get to higher ground.
The 7.5 earthquake that struck North Canterbury just after midnight was felt throughout Hawke's Bay as a long and severe shake, although there have been no reports of damage.
At 12.15am the Hawke's Bay Civil Defence Emergency Management team posted to Facebook "It was a land-based big quake near Hanmer in the South Island. Quite a long one but HB people have no reason to leave home."
This was followed 15 minutes later with "Hi again all - please be advised that this was a land-based earthquake and so there is NO threat of tsunami".
At 12.56am the national civil defence office advised that there was a tsunami threat to the east coast of the South Island and people there should get to higher ground. The office extended this warning to the east coast of the North Island at 1.21am.
At 2.30am the Hawke's Bay CDEM changed its earlier advice and posted a message to Facebook stating:
"Please move to higher ground now. A tsunami alert has now been issued for the North Island including Hawke's Bay. Please text coastal people and share this message".
Despite issuing this warning, the Napier civil defence sirens were not activated.
Twenty-five minutes later there was another post on the CDEM Facebook page saying "The best information we have is that this is a beach warning: stay off the beaches and if you are in a low lying area near the beach move to higher ground. Individual coastal communities are being contacted if necessary and police are clearing campervanners etc off the beaches."
But until at least 3.41am the national office was advising that "The tsunami warning will remain in place until a cancellation message is issued by us. The threat is real. Stay off beaches."
Around 3.30am the local group began evacuating households from the areas in Haumoana, Te Awanga, Waimarama, Ocean Beach and Westshore. At about 5.30am those who evacuated were told they could return home.
Many locals have taken to social media to criticise the actions of the civil defence group over what appeared to be contradictory advice, and asking why the sirens were not used when the evacuation notice was issued at 2.30am.
Hawke's Bay Civil Defence group controller Ian Macdonald acknowledged "that at times it seemed there were mixed messages".
He said modelling showed that the wave would not be large and so a wider evacuation was not required.
"That means we made a conscious decision not to use the sirens. To do so could have panicked a whole population for no good reason and the results could have been worse than the impact of the small wave predicted at that time. The areas were small and therefore we could door knock those people easily," he said.
"Having said that, we are very pleased at the number of people who self-evacuated. While in the end the threat did not eventuate this time, it is really pleasing to know that people know what to do.
"There may be a time when a local earthquake causes a tsunami so suddenly that we don't have time to warn anyone. People should not wait for a siren or a knock on the door: If you feel an earthquake that is 'long or strong, get gone' is the message," Macdonald said.
He acknowledged that at times it seemed there were mixed messages, but that was "the nature of the beast" in that no two emergencies are the same and information changes as events unfold.
"Nature doesn't give us notice and doesn't tell us what sort of affect she's going to have. This was a very long rupture of about 100km long so it was impossible in a very short amount of time to say exactly what would happen along the length of our country. The best we can do is give people what we know, ask that they make some decisions on the best way to react, and then keep updating them as clearer information comes to hand."
He said a 20cm wave was recorded at Napier Port at about 3am and this was believed to have been caused by the earthquake.