Thunder Hole

Thunder Hole

Thunder Hole is one of the most important attractions in Acadia National Park. It consists of a narrow gorge in the southern shoreline of Mount Desert Island. At the end of this gorge is a small cave. The photograph above shows this gorge and the fenced area provided for the safety of people viewing the area. As seawater flows into this cave it splashes out with significant force making a loud noise that is made to seem unusually loud by the acoustical characteristics of the gorge. This sound, coupled with the sound of rolling rocks on the granite floor of Thunder Hole, makes a thunderous noise. The opening of the cave or "hole" is shown in the next photograph. The seawater is receding in this photograph. Note the water dripping from the sides of the hole.

Thunder Hole Opening

In the next photograph, the seawater has entered the hole and is spraying back out of the whole. Note the plants and creatures that have taken up residence on the rock where they can take advantage of the seawater without becoming victims of the spray. Click on this photograph to see a video of two spray cycles. Notice that as the spray makes the loud noise, the camera's sound system attenuates the sound. This video file is 28 megabytes.

Thunder Hole Spray

During violent storms or unusually high tides, the surf in this area is very dangerous as the next photographic montage shows. Under such conditions the observation area is closed. The rocks around Thunder Hole can also be very dangerous during high surf conditions. In 2009, over a dozen people were washed out to sea one nice sunny day because they were standing on the rocks while the surf was dangerously high. One little girl was killed. National Park rangers warned the people to get off the rocks but the warnings were either not heard or were unheeded. Fortunately, the survivors were rescued by the Coast Guard. However, thousands of people were detained in the Thunder Hole area for hours while the park rangers ensured that they could account for everyone.

Thunder Hole in a Storm

Thunder Hole is on the Park Loop Road about a mile (1.6 kilometers) south of Sand Beach. There is a large parking area at Thunder Hole. As shown in the following photograph, Thunder Hole is closed in winter but the portion of the Park Loop Road that passes Thunder Hole is open.

Thunder Hole in Winter


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