Nature Notes

Vol. III January-May 1989 No. 1

Ice Caves

A conversation overheard in the Jackson Visitor Center -- "Boy, I hear the Ice Caves are beautiful." "Yeah, when I was there years ago the blue light was amazing." "Lets go up and explore them." -- end of conversation and maybe the end of a life. The ice caves today are not the same experience as prior to the late 1960's. The story that has evolved is everchanging and directly involves visitors to the caves.

The caves formed in the remnant Paradise Glacier, which is no longer active. This stagnant body of ice and snow has stream openings in the front sections of it, which allows warm air in summer to enter. As the stream rushes out, the air flows back into the ice/snow mass and melts out the internal structure forming the caves. The eerie blue light which illuminates the caves is caused by the thick, compacted ice and the clear, pure water molecules that make up the ice, The incoming light is scattered by the water molecules and gives off the blue light.

Early human records of the ice caves are somewhat murky. It seems that in the early part of the century the ice caves were in the snout of the Paradise Glacier from where the Paradise River originated. However, old photographs indicated the head of the Paradise Glacier has receded back at least 100 meters from 1936 and the corresponding ice cave area is gone. Since the late 1930's the cave areas visited by most people have actually formed in a small lobe of the Paradise Glacier, which feeds Steven's Creek and has been named Steven's Glacier. It is important to note that even in earlier times, changes and collapses were occurring.

In the years after World War II until 1970, the caves were fairly accessible during the summer months. Serious exploration began in the late 1960's. Several exploration trips mapped the known system at that time. Until then only about 1-1/2 miles of cave area was known. In 1978, after all the major exploration was finished, 8.23 miles of cave area had been mapped, consisting of a complex maze of passages. During this active period of exploration, frequent mention was made of the changing nature of the cave system and flakes falling from the walls and ceiling. Flakes are long slivers or chunks of ice which separate from the walls and ceiling because of changes in interglacial pressures.

People were flocking to the cave area to experience the unusual feeling of walking inside the blue, cold world of the caves. Then in the early 1970's record amounts of snowfall occurred and the openings of the caves remained covered with snow a great portion of the time. In the late 1970's and on into the 1980's, the openings have become somewhat more accessible. How accessible the caves have been in the last few years has been directly dependent upon the weather conditions. In years of less than average snowfall and fairly warm summers, the entrances have been accessible in mid to late August. Other years, with higher snowfalls and cooler summers it has been after Labor Day before entrances melt out, if at all. In recent years, there has been an increasing amount of ice chunks and flakes, some the size of a small car, breaking loose and falling from the cave ceiling. The depletion of cave area is primarily a result of weather changes, where loss occurs during years of less than average snowfall and warm summers. These weather conditions expose more of the ice/snow to solar radiation. As a result, more and more of the ice/snow melts away and the overall structure of the cave area is weakened, which causes collapsing. In fact the mapped mileage of 8.23 in 1978 is now probably less than 1-1/2 miles.

The Park Service, for safety reasons, has not encouraged visitors to enter the caves in recent years. The caves are extremely hazardous and probably will never be safe to enter in the future as deterioration continues. Some people seem disappointed that the caves are collapsing and they can no longer visit them as in the past. What is sometimes not realized is that weather conditions and geologic forces occur which can alter features of nature. At times we tend to think of natural scenery in terms of a "picture postcard" where changes do not occur and a moment is frozen in time. In reality changes are always going on in nature. The three mile walk up to the cave area is a beautiful one that unfolds the visual story of change that has naturally occurred from the forces of glaciers and volcanic eruptions. The ice caves are just one page of this everchanging story.

Doug Buehler

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