USDA Forest Service

Fire and Environmental Research Applications Team


Fire and Environmental Research Applications Team
Pacific Wildland Fire Sciences Laboratory

400 N 34th Street, Suite 201
Seattle, WA 98103

(206) 732-7800

Logo of the Pacific Northwest Research Station

United States Department of Agriculture Forest Service.

USDA Link Forest Service Link



Precipitation Identification for Hazard Reduction

This report summarizes a 2-year project. The first phase investigated available technology for remote identification of precipitation type. Next, a precipitation identification (PID) sensor was selected for testing. Later, field and laboratory tests were compared with visual observations. Modifications of the hardware and software were conducted to optimize the use of PID sensors in operational hazard-reduction programs.

A survey of available PID sensors showed that a variety of techniques to determine the phase of precipitation are being developed. Only a few of the PID sensors that are available commercially, however, were found capable of operating reliably in remote mountain locations. Of these, only one was sufficiently cost effective for hazard reduction programs, and it was selected for preliminary tests.

 The test sensor, called HYDROS, was installed at the Washington State Department of Transportation (WSDOT) observation station at Snoqualmie Pass, and was connected to automatic data-logging equipment. Another HYDROS was equipped for mobile use and tested at mountain sites in Alaska, other areas of Washington, and in Japan.

 Data from each sensor were compared against visual observations. The results of this analysis showed adequate performance from the HYDROS, especially when compared with other commercially available PID sensors. The analysis also showed that the HYDROS data can be a valuable asset to the hazard mitigation programs along Washington's mountain highways, especially when combined with data-loggers, totaling precipitation gages, and computer graphics.

Ferguson, S.A.; Breyfogle, S. 1994. Precipitation identification for hazard reduction. Washington State Department of Transportation Final Report, WA-RD 316.2. 44 pp.

U.S. Forest Service - PNW- FERA
Last Modified: Monday, 16 December 2013 at 14:18:40 CST

USDA logo which links to the department's national site. Forest Service logo which links to the agency's national site.