Volcanic lightning explained

Spectacular lightning flashes over Iceland's Eyjafjallajokull volcano. (Photo Credit: Marco, Fulle, Stromboli Online.)

The images are spectacular.

While volcanic lightning is not fully understood, it may give us some clues as to the mysteries of lightning within thunderstorms.

The basic idea when it comes to understanding lightning is electrical charge separation. When electrical charges separate enough to overcome the resistance of the air in between, an electrical discharge occurs. In our home we call this a "door knob shock." In the atmosphere we call it lightning.

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It appears that you need rapidly moving rain and solid objects to create sufficient electric charge separation to produce lightning in thunderstorms. In thunderstorms, this is achieved by hailstones rapidly moving and colliding in violent thunderstorm updrafts which can exceed 100 mph.

In volcanoes such as Iceland's Eyjafjallajokull volcano, it appears to be caused by solid debris being ejected by the volcanic plume. Positive and negatively charged particles separate, and lightning is the result. In this case; really, really SPECTACULAR lightning.

Dr. Greg Forbes of The Weather Channel does a nice explanation here.

Severe weather awareness week:

This is severe weather awareness week in Minnesota and Wisconsin. Though our weather is blissfully quiet for now, it's a good time to brush up on terms, and to check you weather radios for the storms to come. If you have a weather radio that has SAME technology, you can program it to sound alerts only for your county. This is a great value at home or the cabin. You can find a list of SAME county codes here.

Enjoy the sun and low 70s today, as our stretch of May weather continues in April. There is some chance of rain this weekend as a weather system tracks to the south.

Stay tuned.

PH