High Wind — Salt Lake and Tooele Valleys, Utah

2020-09-08 · Salt Lake and Tooele Valleys, Utah

Event narrative

A historic downslope wind event impacted the Salt Lake and Tooele Valleys, with the most extensive damage observed across the Salt Lake Valley. A peak wind gust of 89 mph was recorded at The University of Utah Browning Building. Other notable peak wind gusts recorded included 77 mph at Salt Lake City International Airport, 68 mph at the Great Salt Lake Marina, 68 mph in the Salt Lake City Avenues, 67 mph by the Baccus Highway sensor, 67 mph by the I-215 at Olympus Cove sensor, and 59 mph by the Foothill Dr at Mario Capecchi Dr. sensor. Widespread wind damage, downed trees, and power outages were reported. The Salt Lake Forester estimated more than 1500 trees fell on public land alone, not including private property, during the event. Many of the trees were 60 to 100 years old. Liberty Park lost 69 trees, and the City Cemetery lost 255 trees. Over 180,000 power outages were reported along the Wasatch Front, with some locations taking days to around a week to have power restored due to the extensive damage. Salt Lake City schools were closed Tuesday through Thursday. The Capitol Complex was closed due to extensive tree damage, as were numerous parks, golf courses and recreation areas. Many COVID-19 testing sites were damaged and had to close, including all University of Utah testing sites. The only know fatality for the event occurred in South Salt Lake, when a 61-year-old truck driver unloading his truck was blown over by the wind, striking his head. In addition, Intermountain Healthcare reported that 12 patients were treated for wind-related injuries. Damage and cleanup costs for the event tallied $4.3 million.

Wider weather episode

An abnormal weather pattern for September developed, triggering a significant downslope wind event. Based on climatology and previous case study findings, this type of event most commonly occurs during the winter months. Downslope wind events are often confined to areas near canyon mouths, and usually impact only isolated areas with extreme winds. This event broke the mold in terms of both the early fall timing and extensive spatial coverage of the damage. High winds were reported as far south as the Tooele Valley, with high wind reports all along the Interstate 15 corridor stretching north into the Cache Valley. With the trees having their full canopy, the tree damage all along the Wasatch Front was extreme, with an estimated 4,500 trees damaged in Salt Lake County alone. Current estimates put the cost at $8.9 million. The storm led to 1 fatality, 20 direct injuries, and 4 indirect injuries.

Source: NOAA Storm Events Database, event_id 921694. Narrative written by the NWS forecast office that issued the report.