Science & Research

There is much that we don't know about Jewel Cave. Ongoing research contributes greatly to our understanding and effective management of the cave.

Ultrasonic anemometer recording airflow data
An ultrasonic anemometer measures the speed and direction of airflow.

Airflow Study

Since 2003, a cave climatologist has been conducting a cave airflow study in the Black Hills. He has placed ultrasonic anemometers and temperature loggers in several barometric caves, including Jewel Cave and Wind Cave.

Ultrasonic anemometers are highly sensitive instruments that can measure not only the velocity of airflow, but also the direction, temperature, and vertical flow component. This study is an attempt to better understand the dynamics of cave airflow, to calculate cave volume, and to determine whether or not the studied caves are connected to each other.

At Jewel Cave, airflow has been measured at the Historic Entrance and at constrictions leading to the eastern and western branches of the cave.

Based on these results, it is believed that only 3-5% of Jewel Cave has been discovered, meaning that there could be another 5,000-7,000 miles more.

A microbial sample incubates in Jewel Cave
A sample of "corrosion residue" incubates in a glass tube.  The microbial DNA in the sample will then be sequenced.

Microbiology Study

Many have been curious to know if life can exist in the cave year-round. There are many visitors to the cave including humans, bats, and rats but none truly live there. However, maybe there is something smaller that could live in Jewel Cave. A microbiologist became interested in the life that could exist in the cave.

A pilot study was conducted in 2001 to determine if microbes were present in samples of "corrosion residue," a powdery substance that coats the walls in some cave passages. The pilot study found stalked bacteria, with morphological similarities to organisms found in Lechuguilla Cave, New Mexico.

Ever since the first cave lake was discovered in 2015, there has been more curiosity and potential for microorganisms to exist here. There have been some preliminary investigations which found a microorganism living in the cave lakes, but an official study has not been conducted.

A caver standing in front of a Cave Lake
A caver standing in front of a cave lake for scale.

NPS Photo

Cave Lakes

In 2015 the first cave lake within Jewel Cave was found around 600 feet below the surface where the cave meets the Madison Aquifer. We have discovered over a dozen cave lakes since the first lake was found. The lakes vary greatly in size. The first lake found, Hourglass Lake, is a pool measuring 20 feet by 20 feet. The largest lakes that have been found fluctuate greatly between 100-200 feet long, 20-50 feet wide, 40-70 feet deep depending on water levels.

Since the cave lakes have been found, there has been much curiosity about them. Currently we are monitoring the water fluctuation in two cave lakes to see how the water levels are connected to the precipitation on the surface.

To read the studies that have been done about the cave lakes, click the links below.

Generalized Potentiometric-Surface Map and Groundwater Flow Directions in the Madison Aquifer Near Jewel Cave National Monument, South Dakota

Hydrogeologic Characteristics of Hourglass and New Years Cave Lakes at Jewel Cave National Monument, South Dakota, from Water-Level and Water-Chemistry Data, 2015–21

Groundwater Characterization of the Madison Aquifer near Jewel Cave National Monument, South Dakota

Last updated: September 19, 2023

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Contact Info

Mailing Address:

11149 U.S. Hwy. 16
Building B12

Custer, SD 57730


605 673-8300
The main phone line connects visitors with staff at the visitor center. Throughout the year, the phone line is monitored by staff on a daily basis, excluding holidays and days with limited visitor services. Please be advised that after-hours messages are not taken on the system; visitors are encouraged to call the visitor center during normal operations and speak with a park ranger for assistance.

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