Mountaintop wind gusts almost reach 200 mph (320 km/h) in California blizzard

The Sierra Nevada mountains of California and Nevada are experiencing a rare extreme blizzard this weekend with incredible amounts of snow and strong winds forecast through Sunday including major travel corridors like Interstate 80 over Donner Summit and the Lake Tahoe area. Storm total snowfall may approach 11 feet (3.4 m) in some spots and wind gusts on mountain peaks have been frequently observed over 100 mph (160 km/h).

One station, located at Palisades Tahoe ski resort near the northwest corner of Lake Tahoe, recorded a wind gust of 190 mph (306 km/h) late Friday night. This approaches the California record of 199 mph (320 km/h) set at another mountaintop station just south of here.

When the gust of 190 mph (306 km/h) was recorded at 22:15 Friday, sustained winds were 121 mph (195 km/h). As hurricane categories are determined by sustained winds and not gusts, this is equivalent to a category 3 hurricane. The wind gusts reached high end EF-4 tornado strength.

This mountaintop station sits at an elevation of 8700 feet (2650 m), allowing it to reach into the strong jet stream aimed at the Sierra Nevada. Late Friday into early Saturday the speed of the jet at 500 mb (about 18,000 ft/5,500 m) was around 100 mph (160 km/h). Mountaintop locations along the crest of the Sierra Nevada recorded higher wind gusts resulting from the combination of the strong jet stream and air being squeezed over the top of the peaks causing it to accelerate.

A number of other stations also recorded gusts above 120 mph (200 km/h) along the crest as far south as near Bishop. Lower elevation locations are not experiencing this extreme of conditions. That said, winds are still strong enough to cause blizzard conditions and damage. South Lake Tahoe Airport recorded a wind gust of 58 mph (94 km/h) on Friday.

The blizzard has led to the closure of many roads through the Sierra Nevada including large stretches of Interstate 80 between Sacramento and Reno, Highway 49 to the north of there, and a portion of Highway 89 on the west side of Lake Tahoe.

As of midday Saturday the jet stream has shifted south some to allow for somewhat moderated (but still strong) winds around and above Lake Tahoe. It is forecast to move back northward overnight Saturday into Sunday morning for another shot of strong winds in the mountains above Lake Tahoe before this event ends.

California snowpack has really filled in over the last couple weeks and as of the end of the day on March 1 was right about average for this time of year. This comes after a weak start with barely any snow being observed from the beginning of December to mid-January. Focus now turns from whether or not California’s mountains will get enough snow this season to whether or not the state can keep it into late spring and early summer. The speed of the melt will have major implications for water availability, energy generation, and the wildfire season.

California will be hard pressed to break their 199 mph (320 km/h) all-time record wind gust. For one, gusts that strong are incredibly rare outside of high intensity tornadoes and hurricanes. At wind speeds this high poles and buildings hosting weather stations often fail from collapse or destruction. Additionally, many anemometers are not rated for wind speeds above that threshold meaning that data quality is questionable in stronger winds. There are a few that can handle winds of 224 mph (360 km/h) or higher. I am not sure what model of anemometer is installed at Palisades Tahoe and other nearby ski areas.

The featured image was taken by Carol Highsmith and is at Wikimedia Commons.