Pitot Tube Anemometry at the Mount Washington Observatory

Anemometry is a top priority at the Mount Washington Observatory, home to the fastest winds ever observed by man (231 mph), where they have been measuring wind speed via pitot tube anemometers since 1946. Mount Washington (1917 m asl) is located in the White Mountains of New Hampshire and frequently experiences rime ice accretion rates over 9 inches per hour, an annual average temperature of 27°F, and high wind speeds that in winter reach hurricane force every other day and exceed 100 mph every third day. In these conditions, traditional cup or propeller mechanical anemometers succumb to ice accretion and fail in high wind speeds. By measuring wind speed on the summit by heated pitot tube anemometer, the Mount Washington Observatory is able to collect wind data in the most brutal of meteorological conditions. This paper briefly describes the pitot anemometer system in place from 2011 until 2014 and details the problems and failures of this previous system. This paper also describes the construction, testing, and operational use of a new pitot tube anemometer to begin in 2014 that is able to withstand the severe icing, high winds speeds, and winter weather for which Mount Washington is world famous.