A massive plume of Saharan dust has shrouded swathes of the Caribbean, turning blue skies into a milky-brown haze and sparking health warnings across the region as air quality fell to unhealthy levels.

Strong warm winds over the Sahara desert typically whip up sand at this time of year and carry it thousands of miles across the Atlantic Ocean to the Americas. This year, the dust is the most dense in a half a century, according to several meteorologists. The thick smog has sharply reduced visibility.