After two hours the visibility had improved from 50m to around 200m.
<a rel="nofollow" class="external text" href="https://www.flickr.com/people/40271931@N00">Peter Dowley</a> from Dubai, United Arab Emirates
CC BY 2.0
<a rel="nofollow" class="external text" href="https://www.flickr.com/photos/pedronet/3345030004/">Riyadh sandstorm</a>