The past to days were quite dusty thanks to strong south winds in advance of a slow moving cold front that finally moved into the Salt Lake Valley last night. Yesterday was the worst of it with dust filling the Salt Lake Valley in the afternoon, creating and apocalyptic scene.
Scene looking south over the Salt Lake Valley from the upper Avenues at 6 PM |
Observations from the University of Utah over the past two days show persistent southerly flow on Sunday with peak gusts reaching 40-45 miles per hour. Those winds died down Sunday night before strengthening Monday morning. The strongest winds of the period occurred Monday with gusts > 35 mph common from about 1100 to 2100 MDT and a peak gust of 48 mph.
Source: MesoWest |
A look at MesoWest data shows many valley locations in central and western Utah had peak gusts more than 50 mph. A few examples include Parowan (61), Curlew Junction (60), Stockton (60), Simpson Springs (58), Baccus/SR111 (58), and I-215 at I-80 (58).
The exposed lake bed of the Great Salt Lake gets a lot of attention for dust, but widespread, prolonged events like this tend to be pre-frontal with dust sources to the south, southwest, and west. GOES satellite imagery from yesterday afternoon shows many dust sources over western Utah. With yellow arrows I've highlighted four. The first two are the playa area near Fish Springs in western Utah. Another is in the Skull Valley. A lot of dust was produced in these areas, but did not affect the Salt Lake Valley yesterday (although dust from these areas could have come in with the cold front last night).
Source: CIRA |
The fourth in the southern part of the image and appears to be the Wah Wah Valley Hardpan south of the Sevier Dry Lake Bed. It's unclear if dust from this area reached the Salt Lake Valley yesterday or extended into environs to the east.
The sources for the Salt Lake Valley, however, appeared to be many in the areas that I've circled in blue. There appear to be many emission hotspots in this area, without any one obvious in this visible satellite loop. Just to the west of it though I've identified one clear hot spot that produced a plume that one can clearly trace into the western Salt Lake Valley.
That plume emerges from an area that is near SR-36 between Vernon and Eureka and just to the west of Boulter Peak. This is an area that was burned during the Boulter 2024 fire. My best guess is that the burn scar is the source of this plume (h/t to University of Utah Research Assistant Professor Derek Malia for pointing this out).
Source: https://app.watchduty.org/ |
Burn scars have been important sources of dust for the valley in the past. The Milford Flat Fire (2007) was the largest wildfire in Utah history and its scar was a prolific dust producer for many years. Fortunately, the land surface there appears to have recovered and is more resistant to dust emissions today.