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Ice cave climate monitoring at Sunset Crater National Monument, Arizona

October 24, 2024

The purpose of this project was to monitor the cave climate of the Sunset Crater National Monument “Bonito Flow” Ice Cave. The main purpose of the climate monitoring was to determine if “Ice Cave” was still an ice cave, i.e., a cave that contains perennial ice. The data acquired from 2 March 2021 to 13 Dec. 2022 consisted of temperature, humidity, and pressure throughout the cave structure and included temperature and humidity measures outside the cave, but near the entrance. This cave is considered a sacred spot by at least three southwestern tribes because it was a historical source for ice and continues to be a place for pilgrimages and ceremonies.
Sensors were distributed throughout the cave, but with a focus on a large ice puddle that forms on the cave floor during the winter months. Air temperatures on the cave floor often showed decreases in air temperatures that corresponded to times when the outside air temperatures were below that of the cave air temperature, suggesting the flow of colder air into the cave. Cave air was saturated with water vapor most of the time. An air temperature gradient existed between the cave floor and ceiling. This gradient was greatest during the summer. Hoarfrost was observed on the cave walls and ceiling, indicating that the rock was at or below freezing temperatures.
Sunset Crater Bonito Flow Ice Cave may still be an ice cave, but additional monitoring and analysis is needed. The visible presence of ice at the ice puddle occurred for about 11 out of 12 months each year, but perennial ice may still exist just below the rocky cave floor. The temperature of the floor never went above a few degrees Celsius, and once freezing cold air from the surface flowed back into the cave, it dropped to below freezing. These data therefore suggest that this cave is a static ice cave.

Publication Year 2024
Title Ice cave climate monitoring at Sunset Crater National Monument, Arizona
DOI 10.3133/ofr20241067
Authors Timothy N. Titus, Kaj E. Williams, Glen E. Cushing, Amber L. Gullikson
Publication Type Conference Paper
Publication Subtype Conference Paper
Index ID 70260967
Record Source USGS Publications Warehouse
USGS Organization Astrogeology Science Center
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