Vatnajökull Region is a great place to visit one of Iceland’s natural wonders; the ice caves. The ice caves form during the winter months in the outlet glaciers of Vatnajökull, one of the biggest glaciers in Europe by volume. In the fall, professional local guides go scouting for the ice caves for the coming winter season.
In some countries, you have almost the same ice caves year after year as the temperature there is constant. However, Icelandic caves are different. Each winter the weather cools and conditions change. Guides start looking for new caves, large and safe enough to explore on the inside.
Most of the ice caves are formed as canals for water that run through or at the bottom of the glacier. The water digs its way from underneath the glacier and forms the caves. Usually, they are formed in the summer when the flow of meltwater is at its peak. Then they are full of water and not accessible. When the shedding stops during fall, the flow of water in the cave greatly reduces and usually stops completely throughout the winter. The temperature becomes cold enough to strengthen the ice. As a result, what you have left is an ice cave.
Through the ice wall’s wavy appearance, you can see how the glacial river meandered smoothly through the glacier with visible forms of motion. Inside, you will find a part of the space was completely dark since it’s away from both ice cave openings. When your glacier guides turn their lights off, you will experience the utter quietness inside the ancient glacier as if time has stopped.
The ice caves are only accessible during winter months, from November and usually throughout March, depending on the weather. The beautiful ice caves are very dangerous if you are not accompanied by a trained guide that knows the glacier from the inside out, you should not go there by yourself.
The caves should never be entered without a glacier guide and proper safety gear. Before going into the ice cave with a tour operator, you are provided with a safety helmet and crampons for walking on the ice. The beauty of the cave is breathtaking, with fascinating ice formation, and color.
According to Wikipedia/ visitvatnajokull