Thunder Hole got its name because of the loud sound that waves sometimes make when rolling into the little inlet. This happens because, down low, there is an area worn out of the granite, that goes deeper into the side of the cliff than it appears it does from above. When the wave rushes in, air is sometimes trapped by the force of the wave, creating pressure and then finally releasing the air, with the wave slapping against the little cavern's walls. It has a deep sound, almost like the deepness of distant thunder. It is kind of like the effect you get when you cup your hands as you clap them together.
This is a popular spot for visitors wanting to hear the loud “thunder” sound. The fact is that, it does not happen all of the time. It depends on several things such as the roughness of the seas, the size of the wave, and the level of the tide. When seas are rough at a high tide, the splash from the wave rushing into Thunder Hole's inlet can reach over 40 feet high. At times like this, it can be dangerous being too close. A larger than normal wave can happen unexpectedly, catching one off guard.
If there is a high pressure zone in the Gulf of Maine, this place can be very dangerous. An example is when Hurricane Bill was way out to sea. The weather was not stormy but the waves were dangerously high because they can travel great distances while maintaining their power. And, this, is not released until the wave gets closer to shore at the shallower depths. The message? Be aware of the ocean waves, where you are relative to them, and know if storm fronts are near. Also, always understand that rocks can be slippery when wet. They also can have tiny pieces of rock and sand that can act like tiny marbles when stepped on. Out from under you goes the feet and down you go!
Still, this is one gorgeous spot for spectacular views and photography. Thunder Hole is located on the eastern coast of Acadia National Park on Mount Desert Island. To the north (left) within sight is Sand Beach and Great Head. To the south (right) is Otter Cliff. Being on the east coast, this is the place to be for sunrises.
Photos: All Wet | Wave | Big Splash | Hurricane | HUGE Wave | Sunrise | Surf
Suggestion: The famous Ocean Path goes right by here. It begins near the upper parking lot at Sand Beach and ends to the south at Otter Cliff. The path is 2 miles one way - 4 miles round trip. Consider giving this a try.
The Free Island Explorer Shuttle Bus Service makes regular (in season) stops at the Sand Beach, Thunder Hole, and Otter Cliff. (Refer to their #3 Sand Beach/Blackwoods & #4 Loop Road Routes.) The #3 Sand Beach/Blackwoods Route Bus returns to Bar Harbor at the Village Green and the #4 Loop Road Route Bus stops at the the Hulls Cove Visitor Center.
Thunder Hole Parking GPS Coordinates: Latitude 44.321011; Longitude -68.189330
Hulls Cove Visitor Center GPS: Latitude 44.409286; Longitude -68.247501
Discover Thunder Hole!