How is wind speed measured on Mount Washington?
Wind speed is measured using either of two instruments. When winds are light, a three-cup anemometer records the velocity, as it is especially sensitive. Wind speed is measured by the rate at which the cups turn. However, stronger winds, over 30 miles per hour, tend to put a lot of wear and tear onto such an instrument, and cause its bearings to wear out prematurely. Also, there is no effective means to prevent rime ice from accumulating on a three-cup, and rime ice on such an anemometer can cause poor readings at best, and destruction of the instrument at worst. So high winds and heavy icing – such as are common on Mount Washington, especially in the winter — call for a specialized device, a pitot-static anemometer. Using a customized application for a piece of aviation hardware, the Observatory’s pitot vanes into the wind and measures its speed essentially through the pressure exerted through a hole in the front of the instrument. The reading is then recorded on a wind chart in the
