First upload. This is a DC-10 Air Tanker drop on the Assayii Lake fire in New Mexico.
*edit*
Reading some of the comments I'll answer a few questions here. 
The first plane is called a lead plane, and as the name suggests, it "leads" the air tanker. He is in radio contact with Air attack, who flys around the fire and talks with both ground and air resources. Resources on the ground relay what is needed to air attack, and he relays that to the lead plane, which makes "dry runs" if you will so the tankers can just come in and line up on the drop. There is usually no direct communication with the tankers and ground resources. The smoke is just to give a visual to the tanker on where to start the drop. 
What he drops is called phos-chek. Pretty much liquid fertilizer colored red for visibility. It's not intended to put out fire, but rather slow it's progress. 
On this run, he is extending the retardant line from earlier drops into an area where ground resources haven't made it to yet.

SOURCE: http://www.liveleak.com/