A strange thing has recently started when using three or more blocks of wood. After the smoker starts producing smoke there are several small explosions. At first I thought it was moisture hitting the hot smoke box but I don't think that is the problem now. I believe it may be blocks are flaming and igniting the large concentration of smoke in the box. I never have expierence this before and was wondering if anybody else has. If so, what do I do to prevent this from happening?