Gluggafoss

Gluggafoss, also called Merkjarfoss, drops about fifty-two metres in two stages on the Merkja river, and the reason for its name is the rock: the lower section runs through holes worn into soft palagonite, so the water disappears and reappears through openings that look like windows. Because the rock is soft, the shape is not fixed. Ash from Hekla's eruption in 1947 filled the river and the tunnels and hid much of the fall for decades, until erosion cleared them again. A path runs up the side to a viewpoint level with the upper drop, and there is usually nobody else there despite it being fifteen minutes off the ring road.

Background

Gluggafoss stands in the Fljótshlíð area of southern Iceland, the most prominent of a string of waterfalls on the river Merkjá, which is why it is also called Merkjárfoss; a signpost at the site gives both names. It lies off Route 261, 17.3 kilometres from Hvolsvöllur. The fall is about 52 metres high in two main drops, 44 metres into a narrow recess and then 8.5 metres more in three channels, down a cliff of soft palagonite above and basalt below. The river has bored holes and tunnels through the palagonite, the gluggar or windows of the name. Hekla, about 30 kilometres away, erupted in 1947 and filled the river and tunnels with ash, hiding much of the fall for decades, until erosion cleared them.

Source: Wikipedia, "Gluggafoss"

What you'll find

• Water through windows - holes worn in soft palagonite on the lower drop.
• A shape that keeps changing - the rock erodes fast and the openings move.
• Blocked by Hekla's ash in 1947 - the tunnels filled and took decades to clear.
• A path to the upper level - a viewpoint beside the top drop.

When to go

May to September; reachable most of the year when road 261 is clear. An hour.

Good to know

The upper path is narrow, muddy and unfenced above the drop. In low water the windows are less dramatic than photographs suggest. There are no facilities. The road in is partly gravel.

Nearby

Seljalandsfoss is south; Hvolsvollur and the saga sites are west.

Key facts