Climatology of wind storms in the Owens Valley, CA

The climatology of high wind events in the Owens Valley, California is obtained using data from six automated weather stations distributed along the valley axis in combination with the North American Regional Reanalysis data set. Potential mechanisms for the development of strong winds in the valley are examined. Contrary to the common belief that strong winds in the Owens Valley are westerly downslope windstorms that develop on the eastern slope of the Sierra Nevada, strong westerly winds are rare in the valley. Instead, strong winds are highly bi-directional, blowing either up (northward) or down (southward) the valley axis. High wind events are most frequent in spring and early fall and they occur more often during daytime than during nighttime, with a peak frequency in the afternoon. Unlike thermally driven valley winds that blow up-valley during daytime and down-valley during nighttime, strong winds may blow in either direction regardless of the time of the day. The southerly up-valley winds appear most often in the afternoon, a time when there is a weak minimum of northerly down-valley winds, indicating that strong wind events are modulated by local along-valley thermal forcing. Several hypotheses are proposed to explain the occurrence of wind storms and the results of hypothesis testing will be presented.