Fagradalsfjall & Sundhnúkur: The Fires of Iceland's New Era
A comprehensive guide to the historic eruptions of Reykjanes (2021–2024). Explore the 'Tourist Volcano' of Geldingadalir and the devastating power of Sundhnúkur.
Fagradalsfjall was once a quiet, unremarkable ridge on Iceland’s wind-swept Reykjanes Peninsula. But on March 19, 2021, after 800 years of dormancy, the ground cracked open, signaling the start of a fiery new geological era. What began as a charming “tourist volcano” in a secluded valley has evolved into a formidable volcanic system—encompassing Meradalir, Litli-Hrútur, and the destructive Sundhnúkur crater row—that now threatens the town of Grindavík and the famous Blue Lagoon. This article guides you through the timeline of this historic awakening, separating the “friendly” eruptions of the past from the dangerous reality of today.
1. The Awakening: Geldingadalir (2021)
For weeks, thousands of small earthquakes shook the peninsula, keeping locals awake at night. Then, a red glow lit up the dark winter sky.
The “Tourist Volcano”
The 2021 eruption in the Geldingadalir valley was a geological miracle for spectators. It was small, contained within a deep valley, and produced effusive lava flows (low explosivity). It quickly became a global sensation. Over 700,000 visitors hiked the rugged trails to witness lava fountaining from the main crater. People roasted marshmallows over cooling lava, and drone footage of the “lava rivers” went viral daily. This eruption lasted six months (ending in September 2021), creating a spectacular shield volcano landscape and filling the valley with fresh, black rock.
2. The Sequel: Meradalir (2022)
Just 11 months later, on August 3, 2022, the fires returned. This time, a fissure opened in Meradalir, a valley just north of the 2021 site. While visually similar to the first eruption, it was more powerful, pumping out lava at a faster rate. However, accessibility was harder, and the eruption was short-lived, ending after just 18 days. It solidified the theory that Reykjanes had entered a period of “Volcanic Unrest” that could lasts for centuries.
3. The Aggressive Turn: Litli-Hrútur (2023)
In July 2023, the third eruption began at Litli-Hrútur (“Little Ram”). This was no longer the “cute” volcano of 2021. A long fissure tore open the earth, unleashing a river of lava that flowed rapidly across the landscape. The gas pollution (SO2) was intense, leading to frequent trail closures. Moss fires triggered by the lava spread smoke across the region. It was a warning sign that the system was growing more energetic and less predictable.
4. The Threat to Grindavík: Sundhnúkur (2023–2024)
In late 2023, the volcanic activity shifted dangerously westwards, moving from secluded valleys directly toward infrastructure.
The Evacuation of Grindavík
Before any lava appeared, a massive magma dike intruded beneath the fishing town of Grindavík. It tore the town apart from below—roads cracked, houses slumped, and steam vented from the streets. The entire town was evacuated in a dramatic rescue operation.
The Fissure Eruptions
Starting in December 2023, a series of powerful, short-lived fissure eruptions ripped open north of the town at the Sundhnúksgígar crater row.
- January 2024: Tragedy struck when a fissure opened inside the town’s perimeter defense. Lava consumed three homes, providing heartbreaking images seen around the world.
- Defense Walls: Iceland responded by building massive earthen walls (berms) to divert lava flows away from Grindavík and the Svartsengi power plant. These walls have successfully deflected millions of cubic meters of lava in subsequent eruptions (February, March, May, and August 2024).
The Blue Lagoon
The world-famous Blue Lagoon spa has been forced to close and evacuate multiple times. Lava crossed the main access road, isolating the facility for weeks. While the lagoon itself remains intact, guarded by conflicting walls of earth and stone, operations are frequently interrupted by gas pollution and eruption warnings.
5. Geology: A Rift Torn Apart
Iceland sits on the Mid-Atlantic Ridge, where the North American and Eurasian tectonic plates drift apart. The Reykjanes Peninsula is a “plate boundary oblique rift.” For 800 years, the plates drifted without breaking the surface. Now, that tension is being released. Scientific analysis of the lava shows it is primitive tholeiitic basalt, coming directly from the mantle (15–20 km deep). This suggests a direct plumbing system has been established, meaning eruptions could continue periodically for decades or even centuries.
6. Tourism Guide: Visiting in 2025/2026
Visiting the eruption sites has changed dramatically from the “party atmosphere” of 2021.
Is it safe?
- Access is strictly controlled. Areas around Grindavík are often closed (restricted zones).
- Gas Hazard: Invisible sulfur dioxide can collect in depressions and be lethal. Always check SafeTravel.is before heading out.
- The 2021/2022 Sites: You can usually hike to see the cooling lava fields of Geldingadalir. They are still steaming and hot to the touch.
How to see it
- Guided Tours: Highly recommended. Guides carry gas meters and know the safe paths.
- Helicopter Tours: Offers the safest and most spectacular views of the crater rows and the defense walls protecting the town.
- Best Viewpoints: Hiking trails up nearby mountains (like Langihryggur) offer panoramic views of the new “black wilderness” created by the lava.
7. Frequently Asked Questions (FAQ)
Is Grindavík destroyed?
Grindavík is severely damaged by faulting and partially covered by recent lava flows. It remains largely uninhabited as of 2025, with residents living in temporary accommodation. The future of the town is uncertain.
Is the Blue Lagoon open?
It operates intermittently. It closes immediately if seismic activity suggests magma movement. Always check their official website for real-time status.
Will the eruption stop?
Individual eruptions (like the one in August 2024) typically last a few weeks. However, the volcanic period is expected to last for decades. We are witnessing the birth of a new volcanic field.
Can I touch the lava?
Never. Even black lava can be 500°C inside. A thin crust can hide a molten river. Walking on fresh lava is illegal and suicidally dangerous.
8. Technical Specifications
| Feature | Data |
|---|---|
| System Name | Fagradalsfjall / Svartsengi System |
| Lava Type | Tholeiitic Basalt (low viscosity) |
| Total Area | >10 km² (and growing) |
| Highest Fountains | ~100-300m (Sundhnúkur phase) |
| Major Disruption | Grindavík Evacuation, Blue Lagoon Closure |
| Status | Periodic Fissure Eruptions |
The Fagradalsfjall and Sundhnúkur fires have reminded the world that Iceland is a land in the making. It is a place of raw, terrifying beauty, where the Earth creates new land at the cost of human settlement. It is living geography.