Excerpt from wunderground
A truly wild night in the high Sierra
Two high-elevation weather stations at California’s Squaw Valley resort experienced incredible winds on Monday night as the core of the jet stream associated with the atmospheric river came through, together with localized wind acceleration from a low-level jet encountering the Sierra crest. (Thanks to WU member BayFog for pointing out the multiscale interactions.] Between 10:45 pm and 11:00 pm PST, the Siberia (Sierra Crest)-Squaw station, or SIBSV–located at an elevation of 8700 feet near the top of Squaw Peak–recorded a peak wind gust of 193 mph, with sustained winds reported at 123 mph. During the same interval, only about two miles to the southeast, the Summit (Ward Mt)-Alpine station, or SUMAM–perched atop Mt. Ward at 8643 feet–recorded a gust to 199 mph, with sustained winds of 148 mph.
Extreme gusts over 150 mph are no stranger to the high Sierra. In a 2011 blog post, WU weather historian Christopher Burt referred to an unddated state record gust of 176 mph from the Mt. Ward station. Just last month, on January 8, the same station notched a 174-mph gust. (If it’s any comfort, the atmosphere at this height is about 25% thinner than at sea level, so the wind exerts less force.)
Figure 4. Preliminary data from the summit of Ward Mountain in California’s Squaw Valley ski resort show a gust to 199 mph (highest green dot). The gust occurred between 10:45 and 11:00 pm PST on Monday, February 20, 2017. Image credit: MesoWest/University of Utah via National Weather Service.
The closeness of Monday night’s amazing gusts in both time and space, as part of a multi-hour ramp-up in wind speeds, is a strong clue that the data are likely valid. Also lending credence is the location of these two stations: near ridgetops in a highly wind-prone area. “Everything would suggest that it’s pretty legit,” said John Horel (University of Utah), an expert in Western weather and climate and coordinator of the MesoWest observation network. I also got in touch with Sam Kieckhefer, the public relations coordinator for Squaw Valley/Alpine Meadows. “As far as what people have seen in recent history, it’s definitely the highest [wind gust] that has been noted,” Kieckhefer said of the 199-mph gust. The two Squaw Valley stations were installed in the 1980s, with the Siberia station at close to standard height (10 meters, or about 33 feet); information on the height of the other station wasn’t immediately available. Gusts at these stations are reported every second (i.e., instantaneously), according to Western Weather Group, which works with Squaw Valley on data collection. The 1-second tempo is typical of Remote Automatic Weather Stations (RAWS). It would tend to yield slightly higher values than the 5-second gusts used by stations in the Automated Surface Observing System (ASOS). Still, it appears that the 199-mph gust could be a valid contender for the highest wind gust in California weather annals and one of the strongest gusts recorded near ground level in U.S. history.
Bob Henson and Jeff Masters
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