Yosemite Valley Ahwahnee Hotel Rockfall Monitoring Camera Installation
The camera type would very likely be similar to existing web cameras in Yosemite Valley. It would be housed in a weatherproof container roughly 30 x 10 x 10 inches. The camera would feed data to a hard drive located in the building via a data cable, and the hard drive in turn would be connected to the park intranet via an ethernet connection that would be password protected. The data would be stored for ~5-7 days, after which time it would be overwritten, i.e., there would be no long-term data storage. Camera image and audio data would be for internal use only. Although the primary purpose of the camera would be to monitor rockfall activity, it could also be used to monitor processes such as air quality, smoke dispersal, etc. The resolution of the camera would not be high enough to identify individuals at Glacier Point.
Requirements for the installation site include an unobstructed view of Glacier Point, AC pwer, a high-speed internet connection, a protective structure, and relative security. A small outside landing at the top of the Ahwahnee Hotel (near the top of the elevator shaft) meets all of these requirements. This area is very secure behind a locked door. The landing at the top of the Ahwahnee presently houses two large antennaes and a small satellite dish used by DNC. The landing has large eaves that overhang over the landing and would provide protection for the camera from rain and snow. The northeastern corner of the landing underneath the eaves presents the best setting for the camera, as it is protected and has an unobstructed view of Glacier Point.
THERE WOULD BE NO STRUCTURAL MODIFICATIONS TO THE AHWAHNEE HOTEL ASSOCIATED WITH THIS PROJECT. The camera could either be clamped to an existing handrail that extends around the landing, or placed on a small tripod that could be similarly secured. Wires connecting the camera to the hard drive would join cables associated with the satellite dish and enter the building through existing holes. The hard drive could be situated in the old kitchen on the sixth floor, joining existing satellite dish equipment. The camera would not be easily seen from ground near the Ahwahnee or from Glacier Point. As recommended by the park's Historical Architect, the camera housing would be painted brown and be installed as low as possible to decrease visibility.
Resources Management and Science Historic Architecture and Landscape staff have reviewed this proposal and conducted a site visit, and do not recognize any potential impacts to the Ahwahnee Hotel structure or its historic values; HAL staff would also be involved in the installation. DNC management have also indicated their support of this project. The camera would be in place for a pilot phase of 3 years.
This project proposes to install a camera at the top of the Ahwahnee Hotel to monitor rockfalls from the cliffs below Glacier Point and above Curry Village. These cliffs have produced numerous rockfalls in the past decade that have injured park employees and visitors (including one fatality) and have damaged structures at Curry Village. The Yosemite Valley Plan identifies rockfall monitoring as an important component in managing exposure to geologic hazards. In support of this goal, this project would install a video camera that would constantly monitor the cliffs below Glacier Point. Although still photographs exist of rockfalls in Yosemite Valley, there are few video clips of these events. More importantly, there are none that capture the full event, particularly the moments just before and during rockfall release. In the event of a rockfall from Glacier Point, the resulting image and audio data captured by the camera would be used to fully document the rockfall, including the release point location, mode of failure, volume of material released, and, possibly, the rockfall triggering mechanism. The data could also be used to quickly and safely assess the area(s) subjected to rockfall impact.