Lightning in volcanic ash
If a volcanic eruption is not impressive enough already, try seeing it when lightning is involved. Normally ash and dust are electrically neutral. However, when the two elements are emanating from a volcano they are (obviously) very hot, and can have positively and negatively charged ions. These in turn cause electric and magnetic fields, with the result that the positively and negatively charged ions separate from each other. This process can then add severe lightning to a volcanic ash cloud.
"It could be pretty grim," says California's chief of snow surveys, looking toward the summer months. During one of the worst droughts in centuries, st... More "It could be pretty grim," says California's chief of snow surveys, looking toward the summer months. During one of the worst droughts in centuries, state officials are concerned. The snowy stockpile of water in the Sierra Mountains is the state's real reservoir, supplying about a third of the water used by farms and cities when it melts each spring and early summer. National Geographic followed California’s top snow surveyor on a recent snow inspection, and he's sounding the alarm.
Date 12 hrs ago, Duration 3:19, Views 848
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