Introduction
The largest icebergs calve from the ice shelves of Antarctica. These tabular icebergs can be enormous, sometimes rivaling small countries in area.
Icebergs are tracked by satellite and given alphanumeric names based on the Antarctic quadrant where they originate. They can drift for years before melting.
1. Iceberg B-15
- Area: 11,000 km² (at calving)
- Length: 295 km
- Calved: March 2000, Ross Ice Shelf
B-15 is the largest iceberg ever recorded. When it broke off the Ross Ice Shelf in 2000, it was larger than Jamaica and nearly as big as Connecticut.
Fragments of B-15 were still drifting in the Southern Ocean over 20 years later. One piece blocked McMurdo Sound for years, threatening penguin colonies.
2. Iceberg A-76
- Area: 4,320 km²
- Length: 170 km
- Calved: May 2021, Ronne Ice Shelf
A-76 was the largest iceberg in the world when it calved in 2021. At 170 km long, it was about the size of the Spanish island of Majorca.
3. Iceberg A-68
- Area: 5,800 km²
- Length: 175 km
- Calved: July 2017, Larsen C Ice Shelf
A-68 made headlines when it calved from the Larsen C Ice Shelf in 2017. It drifted toward South Georgia Island in 2020, raising fears it could ground on the seafloor and disrupt wildlife.
4. Iceberg A-23A
- Area: 4,000 km²
- Status: Grounded for decades, freed 2023
- Location: Weddell Sea
A-23A was grounded on the seafloor of the Weddell Sea for over 30 years before breaking free in 2023. When it started moving, it became the world's largest active iceberg.
5. Iceberg B-15A
- Area: 6,400 km² (largest B-15 fragment)
- Drift: Traveled to New Zealand waters
- Duration: Tracked for 18+ years
B-15A was the largest fragment of the original B-15 iceberg. It drifted for over 18 years and was tracked as far north as New Zealand before breaking up.
6. Iceberg C-19
- Area: 5,500 km²
- Length: 200 km
- Calved: 2002, Ross Ice Shelf
C-19 calved from the Ross Ice Shelf in 2002. It blocked the path of sea ice out of the Ross Sea, causing a backup that affected penguin breeding colonies.
7. Iceberg D-16
- Area: ~310 km²
- Length: ~29 km
- Calved: 2006, Fimbul Ice Shelf
While smaller than Antarctic giants, D-16 demonstrated that icebergs can calve from ice shelves all around Antarctica, not just the largest ones.
8. Iceberg T-1 (Petermann)
- Area: 260 km²
- Calved: 2010, Petermann Glacier, Greenland
- Significance: Largest Arctic iceberg in decades
When a 260 km² chunk broke off Greenland's Petermann Glacier in 2010, it was the largest Arctic calving event in nearly 50 years. It signaled accelerating ice loss in Greenland.
Key Facts
- Iceberg B-15 (11,000 km²) was larger than Jamaica.
- Only about 10% of an iceberg is visible above water.
- Antarctic icebergs are tracked by satellite and given alphanumeric names.
- Fragments of B-15 were still drifting 20+ years after calving.
- Iceberg calving from Antarctic ice shelves has accelerated in recent decades.
Fun Facts
- B-15 was so large it was visible from space without magnification.
- A-68 headed straight for South Georgia Island, home to millions of penguins, but broke up just in time.
- A-23A sat grounded on the seafloor for over 30 years before ocean currents freed it.
- Icebergs can contain fresh water worth billions of dollars; plans to tow them to arid regions have been proposed.
Final Thoughts
The largest icebergs are awe-inspiring demonstrations of the scale of Earth's ice sheets. As climate change accelerates ice loss, these massive calving events are becoming more frequent and more significant.
