Fagradalsfjall

The Reykjanes peninsula had not erupted since the thirteenth century when, in March 2021, fissures opened at Fagradalsfjall and lava began to fill the valleys of Geldingadalir - the start of a new eruptive episode that has continued in pulses at this and neighbouring fissure systems since. The 2021 eruption was unusually accessible and safe to approach, and tens of thousands walked out to watch lava fountaining a few hundred metres away, which is rare anywhere. Later eruptions in the same system have been more dangerous and have threatened Grindavik and the infrastructure around it. What is walkable and what is closed changes with the activity, and official hazard assessments govern access.

History

The mountain formed in an eruption under the ice sheet in the Pleistocene and had lain dormant for 6,000 years, while the wider peninsula had been quiet for nearly 800 years, since the end of the Reykjanes Fires in 1240. After an earthquake swarm from December 2019, on 19 March 2021 a fissure opened in Geldingadalir south of the mountain, and its lava field is named Fagradalshraun (Wikipedia, Fagradalsfjall).

What you'll find

• A peninsula awake after 800 years - the fissures that opened in 2021.
• Fresh lava fields - the flows that filled Geldingadalir and beyond.
• Marked trails over new ground - routes that shift with each episode.
• A live hazard picture - access decided by current assessments, not by season.

When to go

June to September for walking; only when access is officially open. A day.

Things to know

This is an active volcanic zone and conditions change fast - gas, unstable crust and new fissures are real risks, and closures happen at short notice. Check the official hazard status the same day. There may be no visible lava at all. Trails are rough and weather is exposed.

Nearby

Grindavik and the Blue Lagoon are close; Keilir stands on the same lava plain.

Key facts