Monday, April 16, 2018

Where Today's Dust Is Really Coming From (Not Sevier Lake)

The Wasatch Front has long had episodes of poor air quality related to elevated PM2.5 concentrations during our dreaded wintertime inversions.  We have also seen episodes of elevated and sometimes unhealthy PM2.5 concentrations due to blowing dust.  There are multiple dust sources in southern and western Utah, but this winter, the Cedar Valley west of Utah Lake has been especially productive.

One of our post-docs, Derik Malia, first brought this source region to my attention in December.  In my blog post on December 21, we discuss two major dust plume events that clearly originated from the Cedar Valley on 3 December and 19-20 December.  Below are MODIS imagers of those two events clearly showing the plume extending from the Cedar Valley to the Salt Lake Valley.

Today?  Same story.  The latest MODIS shows the Cedar Valley is the primary source for the dust impacting the Salt Lake valley.  Look at the clear plume that begins just to the west of Utah Lake.

Sadly, media reports, such as the one below in the Deseret News (available in full here), are stating that the dust is coming from the Sevier Lake Bed.

This is also being suggested in the tweet below from the Utah DEQ.

The Sevier Lake Bed can be an important source for dust, but in the MODIS image for this afternoon, that dust is going northward into the West Desert (look closely).  Our dust today, and in the December events, is coming primarily from the Cedar Valley.

These plumes are repeatedly impacting over 1 million people in the Salt Lake County and portions of Utah County.   Dust from these plumes, once deposited on the Wasatch snowpack, result in an accelerated snowmelt due to greater absorption of solar radiation.  

Reducing emissions from the Cedar Valley won't eliminate wind-blown dust events, but it would certainly reduce the frequency, duration, and severity of these episodes in the Salt Lake Valley.


  1. Jim, we were driving south on I-15 that day and we could see the plume coming from the far side of Utah lake. There were also clear major sources of dust from the aggregate site at Thanksgiving Point. Once we were south of those, the air was much clearer. You should be able to track the difference on as well.
    There was a further major amount of dust coming from a dirt road which happened to be aligned parallel to wind flow south of Nephi. But the plume from west of Utah lake was the spectacular one.

  2. What kind of operation is producing the dust in the Cedar Valley? Could it be the open pit mining in the Mercur gold mine location (google map:

    1. The Mercur Mine is too far northwest to be the source of this dust. More likely coming from areas about 5-6 miles WNW of Mosida.