File:Chihuahuan Dust over New Mexico, Texas, and Mexico (MODIS 2021-03-21).jpg

English: Gusty springtime winds turned the skies yellow and beige in mid-March 2021 across northern Mexico, New Mexico, and west Texas. A strong low-pressure system blowing along the Mexico-United States border scattered dust in an unusually long-lasting storm.

Sustained winds of 35 to 45 miles (55 to 70 kilometers) per hour —with gusts to 65 (100)—lofted abundant streams of dust from the Chihuahuan Desert. The storm lasted nearly eight hours, reduced visibility to below a half-mile in some places, and degraded air quality, particularly in the El Paso-Juárez metropolitan area. The Moderate Resolution Imaging Spectroradiometer (MODIS) on board NASA’s Terra satellite acquired this true-color image of plumes of shifting sand across New Mexico, western Texas, and Mexico on March 16, 2021.

The brightness of White Sands, New Mexico stands out in the north. Moving due south, the city of El Paso, Texas sits on the Rio Grande—the ribbon of green that serves as a border between western Texas and Mexico after passing through the entire state of New Mexico. A swath of shifting dust measuring more than 105 miles (170 km) wide and about 200 miles (322 km) from north to south is easily visible.

The Chihuahuan Desert has been experiencing drought conditions recently, leaving the desert even drier than usual and primed for dust storms. Even though the storm was quite expansive, it’s not the size that makes this particular dust event notable—it’s the duration. Due to the relatively slow passage of windy conditions, El Paso experienced dusty weather basically for eight hours nonstop—more than twice as long as the historical average for dust events in the city.

Strong winds can move heavier sand grains tens of miles near the ground, while finer grains and dust particles can be carried hundreds to thousands of miles. Just this week, particles from a March 13 dust storm in northern Mexico and New Mexico mingled with the snow falling in Colorado, hundreds of miles to the north.