High Wind — Northern Wasatch Front, Utah

2020-09-08 to 2020-09-09 · Northern Wasatch Front, Utah

Event narrative

A historic downslope wind event unfolded along the Northern Wasatch Front. The peak wind gust for the event, not only in this zone, but across the state, was a 99 mph peak wind gust recorded by the US-89 at Park Lane sensor. Other notable peak wind gusts included 97 mph at Farmington, 84 mph at Hill Air Force Base, 82 mph in North Brigham City, 75 mph at Brigham City Regional Airport, 75 mph at Centerville, and 64 mph at Ogden-Hinckley Airport. Extensive wind damage was reported along the entire Wasatch Front, with widespread downed trees, damaged roofs and power outages. Transportation was heavily impacted with all major north-south (Interstate 15, Interstate 84, and U.S. Highway 89) routes closed or restricted at times through the event. At least 50 semitrailers were overturned, with four truck drivers with injuries taken to hospitals. 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. All school districts were closed Tuesday, with some closures continuing into Wednesday. Two Ogden hospitals reported significant damaged, and an Intermountain Life Flight helicopter was severely damaged. At least 20 manufactured homes were heavily damaged in Box Elder County, requiring residents to be transferred to shelters. 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 921689. Narrative written by the NWS forecast office that issued the report.