What is causing the lightning in the middle of the ash cloud?

I was watchin the news earlier, and where all the ash was coming out there was loads of lightning bolts in the middle, whats the reason for this?What is causing the lightning in the middle of the ash cloud?
just like an ordinary cloud the static electricity is created by the millions of tiny particles rubbing against each other. In this case the particles are dust not moisture like regular clouds but the end effect is the same static electricity builds until it creates a spark that we see as lighteningWhat is causing the lightning in the middle of the ash cloud?
More than 150 times in the past two centuries, volcanic eruptions have been accompanied by spectacular displays of lightning. Sometimes broad bolts of lightning streak across the sky. Other times St. Elmo's fire (ball lightning) cascades from above. Sometimes volcanoes produce branching displays such as at Sakurajima (see photo above.) The 1981 eruption of Mt St Helens featured a spectacular display of sheet lightning, with truck-sized balls of St Elmo's fire seen rolling along the ground 29 miles north of the mountain. Other well-known volcanoes that produced lightning include Vesuvius (1944), Krakatau (1990's), Surtsey, the new volcanic island in Iceland (1963), and Paracutin, the cinder cone that grew out of a farmer's field in Mexico (1940's.)



The cause of volcanic lightning is not completely understood. Geologists assume that the cause is similar to the cause of lightning in thunderstorms, which is also not completely understood.What is causing the lightning in the middle of the ash cloud?
It acts just like a real cloud. The dust and ash is moving very fast rub together causing static charge in the cloud which causes lightning. In normal lightning it is the particles in the air that cause the friction that sets of the charge and creates lightning bolts. I think this is what happens. You should google it.
Considering the fact that not only do you have all that dust and the electric charges from the collision of all those particles but beneath that ash cloud considerable heat. That heat translates into more thermal energy as well so it stands to reason that lightning can be witnessed in such an event. http://volcanoes.usgs.gov/ash/ashfall.ht鈥?/a>



As you can see from the above the link the pictures are quite colorful and intriguing. One of the pictures as you go down show a bubbly looking cloud base reminiscent of CBMAM (Cumulonimbus Mammatus). Those are very turbulent cloud bases at the bottom of a thunderstorm.