Flames coming out the chimney top

My neighbor was watching my biochar burn yesterday and was surprised to see the flame go all the way through the chimney and even out of the top. I have a 55 gallon barrel and I do a TLUD.    The chimney is about 3 feet tall and 10 inches wide.  I figured that it was a sign of a healthy burn.  My impression was that we want the flames to be burning the gases coming off of the wood rather than the wood.  It also led me to believe that some of the smoke was being reburned in the process, like a catalytic converter in a car.  Eventually, toward the latter half of the burn, the wood pile went down, of course, and the flames no longer went up to such heights.

I had very, very little smoke and the most biochar output ever.  I don't have any college degrees in science and I don't have any special insights into the physics of fire.  Does that sound like a healthy fire? It felt that way to me, but like I said, I am not especially educated or experienced in these areas.

Thanks,
John S
PDX OR

Hi John,
I'm no expert either, but the fact that there was little smoke, or at least little visible smoke tells me the fire was hot enough to burn a lot of the gasses. And if you got lots of biochar, which is what you wanted... I'd say you had a pretty successful burn :)

^^ What Matt said.