South Texas Blowing Dust and Smoke
March 18, 2008

Images Description

A complex mix of air pollution from a variety of sources impacted South and Central Texas on Tuesday, March 18th. Strong gusty northwest winds along and behind a cold front caused blowing dust in parts of South Texas, as well as Central and Northeastern Mexico. The most intense blowing dust in Texas was downwind of exposed soil in areas along the Rio Grande. Wind gusts as high as 53 miles per hour were reported at Hebronville and Edinburg in South Texas. The highest measured daily average PM10 was 201 micrograms per cubic meter at the Laredo Continuous Ambient Monitoring Station (CAMS) 44, which rated as, Unhealthy for Sensitive Groups, on the U.S. Environmental Protection Agency (EPA) Air Quality Index (AQI)Exit the TCEQ. scale. The Laredo Airport visibilities did not indicate very high dust levels and satellite imagery also did not show widespread dust in the Laredo area, so the dust measured at Laredo CAMS 44 was probably a localized plume of dust affecting a relatively small area. Measured PM10 also reached "Moderate" levels at Mission CAMS 43 and Brownsville CAMS 80. Ahead of the cold front, continental haze combined with light amounts of smoke from Mexico and Central America raised fine particulate into the "Moderate" range in much of South and Southeast Texas. The strong winds also aggravated a few wild fires in South Texas and a large forest fire in the mountains southwest of Monterey, Mexico. The forest fire sent a large smoke plume aloft into South and Central Texas. A large intense dust plume from the high plains of Central Mexico also was transported aloft over the southern half of the state in the afternoon and evening and rain formed in this dust layer, causing muddy rain in northeastern portions of South Texas and in Central and Southeast Texas in the evening, including the Corpus Christi, San Antonio, Austin, and Houston areas. In Monterey, Mexico, winds gusted to 69 mph and visibility dropped below one mile for around seven hours, indicating PM10 levels probably in the "Hazardous" range. This dust cloud was transported southeastward by surface winds and reached Ciudad Victoria in the late afternoon.

Some airport minimum visibility and peak wind gust observations are shown below:
Airport Location Lowest Visibility (miles) Peak Gust (mph)
Torreon MX 0.25 29
Monterey MX 0.5 69
Matamoros MX 0.5 55
Reynosa MX 0.5 39
Edinburg 1.75 53
McAllen 1.75 51
Saltillo MX 2.5 30
Harlingen 3 52
Ciudad Victoria MX 3 46
Nuevo Laredo MX 4 46
Port Isabel 4 45
Hebbronville 5 53
Brownsville 5 52
Laredo 7 51
Falfurrias 7 45
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