Sources and method

The facts and their sources

1. The Katla ice cave can be visited in every month of the year. troll.is, read 4 Nov
2. At Katla, the ice cave's walls are covered in volcanic ash left by past eruptions. www.mountainguides.is, read 4 Nov
3. Vatnajökull's natural ice caves can only be visited in winter, from November and usually through March, depending on the weather. visitvatnajokull.is, read 4 Nov
4. Ice absorbs a little red light; in very dense glacier ice, light travels deep before coming back out, which gives the ice a blue tint. nsidc.org, read 4 Nov
5. Near Skaftafell, ice cave tours go onto Falljökull glacier and combine a guided glacier walk with a visit to a natural ice cave. troll.is, read 4 Nov
6. Natural ice caves change shape every year, and guides choose the safest cave of the moment. localguide.is, read 4 Nov
7. Vík is about 180 km from Reykjavik, about 2.5 hours by road. www.funiceland.is, read 4 Nov
8. Jökulsárlón is about 380 km from Reykjavik, about 5 hours by road. guidetoiceland.is, read 4 Nov
9. Entering an ice cave without a trained guide is unsafe: walls and ceilings can collapse without warning. guidetoiceland.is, read 4 Nov
10. Most ice cave tours supply a helmet and crampons. visitvatnajokull.is, read 4 Nov
11. Operators ask for warm layers, a waterproof jacket and sturdy boots with ankle support. troll.is, read 4 Nov
12. Operators can cancel or move a tour for weather or safety. www.mountainguides.is, read 4 Nov
13. Book January and February dates early: crystal ice cave tours can sell out weeks ahead. guidetoiceland.is, read 4 Nov
14. Small-group tours set a maximum size, for example 12 participants per guide. localguide.is, read 4 Nov
15. You need no experience for an ice cave tour, though operators advise being reasonably fit so the tour stays comfortable. adventures.is, read 4 Nov
16. Some operators advise against glacier and ice cave tours during pregnancy, because the jeep ride is off-road and bumpy. glacieradventure.is, read 4 Nov
17. The caves visited on Katla tours form inside Kötlujökull, an outlet glacier of Mýrdalsjökull. guidetoiceland.is, read 4 Nov
18. Mýrdalsjökull is Iceland's fourth-largest glacier. adventures.is, read 4 Nov
19. The cave takes its name from the volcano under the glacier. perlan.is, read 4 Nov
20. Katla is an old Icelandic woman's name linked to ketill, a kettle or cauldron; why the volcano got it is not recorded. guidetoiceland.is, read 4 Nov
21. Each eruption leaves ash on the ice, snow buries it, and the moving glacier brings it back to the surface as dark bands. adventures.is, read 4 Nov
22. Kötlujökull's caves show dark bands of ash in blue ice, where Vatnajökull's caves are a clean blue. guidetoiceland.is, read 4 Nov
23. The cave changes all the time, so it will not look exactly like photos of it. www.icelandia.com, read 4 Nov
24. Visits run all year because the ice here is low-lying and covered in debris; few Icelandic caves allow that. guidetoiceland.is, read 4 Nov
25. No public road reaches the ice: visitors meet in Vík and finish by super jeep. guidetoiceland.is, read 4 Nov
26. The tracks to the glacier are unsuitable for normal cars and rental 4x4s. guidetoiceland.is, read 4 Nov
27. The cave is less than an hour from Vík. perlan.is, read 4 Nov
28. Each operator from Vík has its own meeting point in the village. guidetoiceland.is, read 4 Nov
29. A typical visit takes about 3 hours from pick-up in Vík. perlan.is, read 4 Nov
30. On one operator's 3-hour tour, 45 to 60 minutes are spent in the cave area. www.icelandia.com, read 4 Nov
31. Tours usually provide crampons, a helmet and a headlamp. guidetoiceland.is, read 4 Nov
32. The guide gives a safety and equipment briefing before the walk. perlan.is, read 4 Nov
33. Operators describe up to about 2 km of walking in all; one tour has a short, steep stretch with a rope. guidetoiceland.is, read 4 Nov
34. Depending on the cave's layout, one operator crosses small wooden bridges over a stream. localguide.is, read 4 Nov
35. Conditions decide the route and the cave visited. guidetoiceland.is, read 4 Nov
36. In winter, November to March, the ice is cold and stable and its colours are deep, but days are short and the road to Vík may be icy. guidetoiceland.is, read 4 Nov
37. In summer the cave stays open but changes shape fast with the meltwater, so the route and entrance are checked again before each visit. guidetoiceland.is, read 4 Nov
38. Summer on the south coast brings near-endless daylight and clear roads. adventures.is, read 4 Nov
39. A guided tour is the only way to reach the Katla ice cave. perlan.is, read 4 Nov
40. Without a certified guide the glacier is dangerous: crevasses, collapsing ice and sudden meltwater; the cave is reassessed daily. guidetoiceland.is, read 4 Nov
41. From the ring road you can see the ice cap, its outlet glaciers and the black sand plains left by Katla's floods. adventures.is, read 4 Nov
42. One operator warns that the tour may not suit people prone to motion sickness or with a back injury. localguide.is, read 4 Nov
43. Wear warm, waterproof layers with a hat and gloves, plus boots that hold your ankles; nothing can be rented at the glacier. guidetoiceland.is, read 4 Nov
44. The last eruption to break through the ice was in 1918. adventures.is, read 4 Nov
45. The Icelandic Met Office monitors the area continuously. guidetoiceland.is, read 4 Nov
46. If Katla stirs, warnings go out and tours stop in advance. perlan.is, read 4 Nov
47. Vatnajökull is the largest glacier in Europe and covers eight percent of Iceland. guidetoiceland.is, read 4 Nov
48. The Crystal Ice Cave lies in Breiðamerkurjökull and is the most visited of Vatnajökull's natural caves. guidetoiceland.is, read 4 Nov
49. Breiðamerkurjökull is an outlet glacier on the south-east edge of Vatnajökull. guidetoiceland.is, read 4 Nov
50. The Crystal Ice Cave takes its name from the clearness of its ice. visitvatnajokull.is, read 4 Nov
51. As the cave most tour companies use, it can get crowded. visitvatnajokull.is, read 4 Nov
52. Most of these caves begin as channels of water running through or under the glacier. visitvatnajokull.is, read 4 Nov
53. They usually form in summer, when meltwater peaks; they are full of water then and cannot be entered. visitvatnajokull.is, read 4 Nov
54. Each autumn, local guides go looking for the caves of the coming winter. visitvatnajokull.is, read 4 Nov
55. Conditions change every winter, so guides look for new caves large and safe enough to enter. visitvatnajokull.is, read 4 Nov
56. Once autumn cold has frozen the tunnels, guided tours run from October to April. guidetoiceland.is, read 4 Nov
57. The manager of Vatnajökull National Park names November to March as the best time, when steady cold makes the ice stronger. guidetoiceland.is, read 4 Nov
58. The ice is at its least stable in October, and April ranks below midwinter. guidetoiceland.is, read 4 Nov
59. Warm spells with wind and rain can flood the caves in winter and close them. visitvatnajokull.is, read 4 Nov
60. Tours reach the edge of the glacier by super jeep, then walk a short, easy way to the entrance. adventures.is, read 4 Nov
61. Tours to Breiðamerkurjökull leave from the Jökulsárlón car park, which gets busy. troll.is, read 4 Nov
62. You can reach the start of the 3-hour tour with a rental car, and sleep at hotels near the lagoon. guidetoiceland.is, read 4 Nov
63. Tours provide and fit crampons, helmets and harnesses on site. adventures.is, read 4 Nov
64. Never enter these caves without a glacier guide and safety gear. visitvatnajokull.is, read 4 Nov
65. Guides review the caves through the winter and choose the route on the day. adventures.is, read 4 Nov
66. Guide to Iceland counts about 2.8% of Crystal Ice Cave departures called off in normal conditions. guidetoiceland.is, read 4 Nov
67. Guide to Iceland describes the Skaftafell cave now visited as a canyon with no roof, good for people who dislike closed spaces. guidetoiceland.is, read 4 Nov
68. The lagoon was formed by the glacier's retreat, and some of its icebergs wash up on nearby Diamond Beach. guidetoiceland.is, read 4 Nov
69. Vatnajökull is at the heart of Vatnajökull National Park, a UNESCO World Heritage Site. guidetoiceland.is, read 4 Nov
70. A glacier cave forms inside a glacier's ice, and people often call it an ice cave. en.wikipedia.org, read 4 Nov
71. Into the Glacier consists of ice tunnels dug by people into the Langjökull glacier, open all year. guidetoiceland.is, read 4 Nov
72. Into the Glacier lies about 2 hours by road from Reykjavik. guidetoiceland.is, read 4 Nov
73. A snowmobile is the only way to reach the natural caves of the Langjökull glacier. guidetoiceland.is, read 4 Nov
74. The Perlan museum in Reykjavik houses an ice cave built by people. guidetoiceland.is, read 4 Nov
75. Perlan's cave runs for 100 metres and took over 350 tons of snow to make. perlan.is, read 4 Nov
76. In August 2024, part of an ice cave collapsed during a tour at Breiðamerkurjökull: one visitor died and another was injured. abc7news.com, read 4 Nov
77. Inside Iceland's ice caves, it usually stays around 0 °C (32 °F) all year; in winter the entrance can feel colder, because of the icy wind. guidetoiceland.is, read 5 Nov
78. Jeans should not be worn on an ice cave tour: denim takes in water and keeps it against your skin. guidetoiceland.is, read 5 Nov
79. Arctic Adventures advises against jeans on its trips, because they get heavy and cold once wet. adventures.com, read 5 Nov
80. A heavy ski coat is not advised: it keeps the heat in, and the sweat chills you once you stop. Three layers let heat out while you walk and keep you warm when you stand still. guidetoiceland.is, read 5 Nov
81. On one 3-hour Crystal Ice Cave tour, the visit to the cave lasts about 30 to 45 minutes. guidetoiceland.is, read 5 Nov
82. On another operator's Crystal Ice Cave tour, about 30 minutes are spent in the cave. nonnitravel.is, read 5 Nov
83. One operator's listing describes the frozen corridor as usually 30 to 70 m long (98 to 230 ft). www.manawa.com, read 5 Nov
84. Parking at Jökulsárlón lagoon is paid. guidetoiceland.is, read 5 Nov
85. In October 2022, South Iceland Police temporarily closed trips to the ice caves at Kötlujökull, pointing to increased earthquake activity in Mýrdalsjökull. island.is, read 5 Nov