Episodic Dust events of Utah's Wasatch Front and Adjoining Region

Episodic dust events cause hazardous air quality along Utah's Wasatch Front and dust loading of the snowpack in the adjacent Wasatch Mountains. This presentation presents a climatology of episodic dust events of the Wasatch Front and adjoining region based on surface-weather observations from the Salt Lake City International Airport (KSLC), GOES satellite imagery, and additional meteorological datasets. Dust events at KSLC average 4.3 per water year (WY, Oct–Sep), with considerable interannual variability and a general decline in frequency during the 1930–2010 observational record. The monthly dust event frequency and total dust flux is bimodal with primary and secondary maxima in Apr and Sep, respectively. Dust reports are most common in the late afternoon and evening. An analysis of the 33 most recent (2001–2010 WY) events at KSLC indicates that 11 were associated with airmass convection, 16 with a cold front or baroclinic trough entering Utah from the west or northwest, 4 with a stationary or slowly moving front or baroclinic trough west of Utah, and 2 with other synoptic patterns. GOES satellite imagery from these 33 events, as well as 61 additional events from the surrounding region, illustrate that emission sources are located primarily in low elevation Late Pleistocene to Holocene alluvial environments in southern and western Utah and southern and western Nevada.