we're skiing on a very active volcano.
In the past we have had serious volcanic mudflows
called lahars coming down through the skilled with no alarm system.
So we got a quite a serious
situation which we have to manage.
These volcanic mudflows are really hazardous.
We've actually measured them at up to 90 kilometres an hour moving down the mountain,
through
where people are skiing.
90 km per hour is far faster than people can ski
The lahar is full of snow, ash and some boulders - it's going to bowl you over and drown you
and smash you against rocks - so the message is all about trying to get people out of the
way.
GeoNet New Zealand's natural hazard monitoring system has a whole lot of seismometers
spread throughout the National Park.
Several of those have got blast detectors - little pressure sensors.
This system Eruption Detection System or EDS that we have got on the mountain system draws
information
from GNS equipment that's in the park From an eruption to the top of the ski
field we've got about 90 seconds before it hits the ski field and
so people need to react really quickly
When there is an eruption
those sensors detect the data and it sends a message here to these speakers
and that then sets the alarms off.
[sound of alarm]
The warning system consists of speakers in the three main lahar paths - where people
are in danger,
so we've got speakers where they need to be, but we haven't got speakers where they don't
need to be.
Loudspeaker: "Move immediately out of valleys to high ground.
This is a volcanic emergency...
...A lahar is expected to pass through the ski area"
This warning system needs to be as effective as it can but it depends on a lot of things.
it depends on people hearing it, and people knowing what to do, and then doing
it.
This is a fantastic place to ski, there's great terrain to ski, but if you're in the
bottom of the valley
when there is a lahar siren going, that message to people is to get out of
the valley.
During tests like the one you have just seen we have people on the ground
watching what people do and how people move and we add up the numbers of
people in the risk zone at the beginning of the warning and at the end
and we look at the percentage of people who get to safety.
This graph shows
the results of these observations from tests over several years.
For each test
there is a proportion of people skiing who are
at risk at the start of the test and a
smaller proportion who have still not got out of the way by the end of the test.
And in this last year we can see about 72% of people were at risk
at the start and a bit over 10% we're at risk at the end.
It can mean anywhere from
a few people to maybe forty or fifty people are still left at risk on the ski area
We also conduct surveys awareness of the skiers and we ask them a range of
questions including what's the right thing to do when there's lahar warning
and we see in the green bars we know the proportion of people who
know all the correct actions in the blue bar we can see about 10 percent of
people in this year
knew some of the actions but the the tan bars are still in the thirty to forty
percent range which concerns us.
That's thirty to forty percent of people who don't know what to do.
We've developed a range of education materials: we have posters and brochures
with hazard maps on them and warning information.
We've added to that with
signs added to the lift towers asking people questions about mudflows and
telling them what to do.
The most important message is:
If you're on the ski field and hear the siren move out of the valleys onto the ridges nearby.
We're continuing to conduct communications and education research
every year to come up with new ideas to further improve people's response.
The systems we have here particularly the EDS system is a unique system
obviously in New Zealand and also around the world.
We've got a number of partners
that support this system such as the Department of Conservation, GeoNet, EQC and
obviously RAL, the ski field.