At the beginning of the summer monsoon season the ground is parched from the dry foresummer. Downbursts from the first storms can create huge dust clouds, as this one at Organ Pipe Cactus National Monument. Visibility can drop suddenly to near zero; don't try to drive through these!

The next image was taken less than two minutes after this one. These dust fronts can move very fast. The third image in this series was taken another five minutes later; the view is rotated to the right of the first two.


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