SURPRISE! Milford Sound is NOT a Sound

Milford Sound, nestled within New Zealand's Fiordland National Park, captivates visitors with its breathtaking vistas of towering cliffs, cascading waterfalls, and lush rainforests. Often hailed as one of the world’s most beautiful destinations, it draws thousands of adventurers and nature lovers from around the globe every year.

Many visitors are surprised to learn that despite its name, Milford Sound is not actually a "sound." It is, in fact, a fiord – a distinction that reflects its geological formation and structure.

This article explains the geological processes that make Milford Sound a fiord environment,   the history of its name, and the scenery experienced in Milford Sound today. 

Fiords Versus Sounds

Definitions and Characteristics

Fiords and sounds look similar; they are both bodies of water typically connected to the ocean. But what sets them apart are the geological processes that formed them. Sounds are generally large sea or ocean inlets that form due to the ocean flooding into a river valley, whereas fiords are formed by the slow movement of glaciers, which shape the land into deep troughs, and when the glaciers eventually retreat, seawater floods into the valleys they leave behind.

These different geological processes also result in different scenic environments between sounds and fiords. Because sounds are flooded river valleys, they tend to have a more gentle, open coastal environment. In contrast, fiords are usually deeper, narrower, and surrounded by steeper mountain slopes. 

New Zealand Examples

A well-known example of true sounds is New Zealand's Marlborough Sounds, a collection of sea-drowned river valleys located at the northeast corner of New Zealand's South Island. These sounds formed as a result of tectonic movement deep inside the Earth over millions of years, which caused the land to tilt and lower into the Cook Strait. By around 14,000 years ago, seawater was able to flood into the land's river valleys, creating a large stretch of scenic coastline. 

All of New Zealand's true fiords are located in Fiordland, and most of them are not named as fiords but as either sounds or inlets. Milford Sound, Fiordland's most famous fiord, fits the fiord profile perfectly. Its sheer cliffs rise hundreds of metres from the water, and its deep, narrow channel stretches far inland, showcasing its glacial origins. Like all of the fiords in Fiordland, Milford Sound, despite its name, is a true fiord, formed by the forces of ice and time.

Formation of Milford Sound

Milford Sound, or Piopiotahi in Māori, owes its breathtaking scenery to the immense power of glaciers that sculpted Fiordland’s landscape during the last Ice Age. Over 20,000 years ago, colossal ice sheets flowed down from the mountains and out to sea, eroding the landscape and creating steep-sided valleys with flat floors. This process, known as glacial plucking and abrasion, created large U-shaped valleys typical of fiords. When the glacier that formed Milford Sound eventually retreated around 14,000 years ago, it left behind a dramatically carved landscape. The valley, flooded by seawater, became what we now recognise as Milford Sound, plunging to 400 meters deep in some areas.

The post-glacial environment of Milford Sound has been further shaped by rainfall, which feeds numerous waterfalls cascading down the cliffs into the deep fiord waters. The unique mix of fresh and saltwater creates a rich and diverse marine ecosystem, adding another layer of intrigue to the natural wonder of Milford Sound.

Māori Heritage of Milford Sound

Exploration and Naming

Long before European explorers arrived, Milford Sound was a place of profound significance to Māori, the indigenous people of Aotearoa, New Zealand. They named the area Piopiotahi, a name deeply rooted in culture and storytelling that translates to "a single piopio," a now-extinct bird. According to Māori legend, Piopiotahi commemorates the sorrow of the piopio bird, mourning the death of its demigod travel companion, Māui, who died in battle attempting to secure immortality for mankind.

Cultural Importance

Piopiotahi was a vital part of Māori life. The fiord served as a navigational landmark and a rich resource site. Māori tribes traveled to the area for hunting, gathering, and fishing, taking advantage of abundant marine life and sheltered waters. The fiord’s rich supply of sustenance and materials fostered a deep connection between the people and the land.

Their intimate knowledge of Fiordland’s rugged terrain and waterways was crucial for their survival and exploration. The name Piopiotahi, reflecting both nature and legend, signifies the deep respect and spiritual connection that Māori have with the area. Recognising Piopiotahi's Māori heritage and first name is crucial to respecting and preserving the indigenous heritage that adds depth and meaning to the natural landscape.

The Milford Sound Misnomer

European Naming

The name "Milford Sound" reflects a blend of historical curiosity and linguistic legacy rather than geological accuracy. The misnomer traces back to early European explorers and settlers who were unfamiliar with the distinctive processes that shaped New Zealand’s Fiordland environment. In 1809, Welsh sealer John Grono named the area Milford Haven, drawing inspiration from a similarly striking coastal area called Milford Haven in his hometown of Pembrokeshire in Wales.European explorers often applied familiar terms from their homelands to the landscapes they found. To the early European explorers, Milford Sound’s deep, navigable waters resembled the sounds they knew from Europe. In 1851, a Welsh explorer named John Lort Stokes named the area Milford Sound, and this version of the European name has stuck.

Persistence of the Name

The term "sound" became ingrained in the local English language of the area, perpetuating the misclassification. Additionally, cartographers and settlers in the 19th century often prioritised naming places for practical navigation and identification rather than precise geological definitions. This naming convention is demonstrated throughout Fiordland, where the other fiords, like Doubtful Sound, are similarly misnamed. 

Although we now know that Milford Sound is not a sound, this version of its European name has continued through to today, tied to the area's early European history. The Milford Sound name is recognised worldwide, with the area attracting thousands of visitors every year to marvel at the scenery.

Milford Sound Today

Unique Scenery and Environment

Today Milford Sound, or Piopiotahi, is one of New Zealand's most popular tourist destinations, offering a spectacular array of natural features to captivate visitors. The glacier-carved fiord is renowned for its towering cliffs, some of which rise over 1,500 meters from the sea floor. Among these giants is the iconic Mitre Peak at 1690m, a prominent landmark whose sharp, triangular shape earned its name from its resemblance to a bishop’s mitre.

Milford Sound is also famously one of the wettest places on Earth, where waterfalls cascade down the cliffs year-round, with the most famous being Stirling Falls and Lady Bowen Falls. Stirling Falls drops 155m into the fiord waters and is a favourite waterfall to see up close for many visitors on a Milford Sound Cruise. Lady Bowen Falls is the highest waterfall in Milford Sound, plunging 165m into the fiord, and it also provides the electricity and water supply for the Milford Sound township.

After heavy rainfall, the steep cliff sides in Milford Sound also come alive with countless temporary waterfalls springing from the mountain tops. The combination of rugged peaks and waterfalls set against lush rainforests offers visitors stunning views at every turn. The heavy rainfall and waterfalls create an equally spectacular marine environment in the fiord, where a dark, tannin-stained layer of freshwater from the forest-covered mountains sits on top of the salt water, supporting a rich array of marine life that would usually only be found at much greater depths. This unique environment provides abundant food sources for rare species like dolphins, seals, whales, and penguins to feast on, allowing them to pay multiple visits to the fiord throughout the year. 

Experiencing Milford Sound

The surrounding area is rich with hiking opportunities, such as the renowned Milford Track, often described as one of the finest walks in the world. In Milford Sound itself, there are opportunities to explore by tour, boat, kayak, diving, or on foot, all offering visitors a chance to experience the dramatic landscapes and vibrant ecosystems. The fiord's fascinating scenery, both above and below water, combined with its geological and cultural history, makes Piopiotahi, Milford Sound, a destination offering a journey into New Zealand's fascinating geological and cultural heritage.

Milford Sound, or Piopiotahi, is a natural marvel that reveals a narrative of geological wonder and cultural heritage. Contrary to its name, Its steep cliffs, carved by the relentless force of ancient glaciers, showcase the geological story of a fiord formation, and its landscape, with its dramatic waterfalls and lush rainforest, is a living testament to the power of natural forces over time.

Today, Milford Sound attracts thousands of visitors everyday who come to experience its unique blend of natural and cultural history. Whether exploring its waters or trekking its trails, visitors have the opportunity to witness the results of nature's artistry and the deep-rooted cultural connections that have defined Piopiotahi-Milford Sound’s remarkable landscape for centuries.