Visitors to Milford Sound should be aware of various natural hazards before traveling.
Aotearoa New Zealand
- Powerful natural forces have shaped Aotearoa New Zealand over millions of years. Earthquakes and volcanoes lifted these beautiful islands out of the Pacific Ocean. They have created the dramatic landscapes we enjoy today.
- Natural hazards are part of life here. Around 20,000 earthquakes are recorded each year. Most are small and go unnoticed, but larger events can cause damage. Understanding the hazards and how to stay safe is an important part of planning your visit.
Piopiotahi Milford Sound
- Dramatic and ever-changing, Piopiotahi Milford Sound is one of the world’s most spectacular and special environments. Its steep, glacier-carved mountains and deep fiord have been shaped by powerful geological forces over millions of years.
- The area is exposed to risk from a range of natural hazards. These can occur at any time, and some can happen without warning. Of all the hazards, large earthquakes, landslides and tsunamis pose the greatest risk to people at Piopiotahi Milford Sound.
- It is extremely unlikely that one will happen during your visit, especially for a short stay. However, there is a risk and the longer you spend there, the higher it becomes. Once you are there, your safety options are limited and it is important you understand the risks, before you go.
Earthquakes at Piopiotahi Milford Sound
- Like the rest of Aotearoa New Zealand, small earthquakes occur regularly in Fiordland. We don’t feel them and they don’t bother us. These small movements are a normal part of how the land works and do not pose a risk to people.
- Sometimes, earthquakes in or near Fiordland are felt at Piopiotahi Milford Sound. They might shake objects on a shelf or rattle a window, but they do not cause major impacts or disrupt your visit.
- Occasionally, a stronger earthquake can trigger avalanches, rockfall or landslides. These can cause debris to fall onto roads, jetties and tracks, and may disrupt your travel plans if you happen to be nearby.
- Large earthquakes are rare, and extremely unlikely to happen during a short visit. But they will happen again.
- The Alpine Fault runs almost the entire length of the South Island and crosses the entrance to Piopiotahi Milford Sound. It can generate earthquakes of magnitude 8 or greater, occurring on average every 300 years. There is a 75% chance of this happening in the next 50 years (find out more at af8.org.nz). An earthquake of this size would almost certainly affect the narrow waterway and surrounding area.
What to do in an earthquake:
- DROP, COVER and HOLD until shaking stops. Most injuries from earthquakes happen when you try and move during the shaking. The lower to the ground/floor you are, the less likely you are to be injured.
- Follow staff instructions and/or move up and away from waterways (the fiord and rivers) as quickly as possible.
Landslides at Piopiotahi Milford Sound
- The steep mountains around Piopiotahi Milford Sound are prone to rockfall and landslides. Earthquakes and severe weather can make the cliffs unstable, sending rock and debris down at speed.
- Smaller rockfalls are common but often go unnoticed, unless you are nearby.
- Bigger landslides do not happen often. The chance of one occurring during a short visit is extremely unlikely. However, they could cause a tsunami in the fiord and do pose a risk to life at Piopiotahi Milford Sound.
- Large earthquakes are the most common trigger of big landslides in Fiordland. A large earthquake during your visit is extremely unlikely, especially for a short stay.
Be prepared for landslides
- Take extra supplies, food, water, first aid, clothes in your vehicle when travelling in remote areas, in case you get stuck – The road from Te Anau to Piopiotahi Milford Sound, is prone to avalanches, rockfall and landslides. It is monitored 24/7 by the Milford Road Alliance. However, if you get stuck, it will take time for help to reach you. Having extra supplies in your vehicle will make the wait time more comfortable.
- If you see or hear a landslide entering the water, dust clouds, loud rumbling, or splashing. Follow staff instructions and/or move up and away from waterways (the fiord and rivers) as quickly as possible.
Tsunami at Piopiotahi Milford Sound
- Like all of Aotearoa New Zealand’s coastline, Piopiotahi Milford Sound is at risk of tsunami from multiple sources.
- The most common threat comes from distant earthquakes in the Pacific Ocean. These ocean-source tsunamis take hours to reach our shores. Official warnings are issued in time for people to move to safety.
- Less common, but of more concern, is the potential for a large landslide to fall into the fiord and trigger a tsunami.
- Landslide-triggered tsunamis are rare. The chance of one occurring during your visit is extremely unlikely. However, they can create large waves and do pose a risk to life at Piopiotahi Milford Sound.
Be prepared for tsunamis
- Triggered by an earthquake – If you feel a LONG (1 minute or more) or STRONG (cannot stand up) earthquake, while at Piopiotahi Milford Sound, Get GONE. Move up and away from waterways (the fiord and rivers) as quickly as possible.
- Triggered by a landslide – If you see or hear a landslide entering the water, dust clouds, loud rumbling, splashing or unusual water behavior, GET GONE. Move up and away from waterways (the fiord and rivers) as quickly as possible.
Plans and preparedness
- Piopiotahi Milford Sound has emergency response plans. These coordinate multiple agencies in a State or Emergency. The plans cover earthquakes, tsunami, landslides, avalanches, flooding, severe weather and other emergencies.
- All tourism operators maintain their own emergency procedures. These integrate with the wider response in a State of Emergency.
- If a large landslide triggers a tsunami, there will be no warning. Emergency support will take time to arrive. Visitors and workers should be aware of the risk to life and prepared to move up and away from waterways (the fiord and rivers) as quickly as possible.
For more detailed information, please visit Emergency Management Southland or AF8.
