I realized this the other night, which was cold even by NYC standards, prompting me to sleep with a fleece blanket. After a few hours, I woke up hot and kicked off the blanket. As I did, a small static electrical storm erupted -- I could actually see little sparks of electrostatic discharge.
It looked just like the Monster when it's scanning Eko (minus, of course, the mental slide show). So I did a little research and learned that electrostatic fields can suspend particles much like magnetic ones. This website shows how to build magnetic and electrostatic field viewing bottles.
Basically, Smokey is an electrostatic capacitor like a lightning cloud. The friction of its particles generates a charge that must periodically be released. This may explain why Smokey blasts trees when it moves quickly -- it's releasing the extra electric charge generated by its agitation.
This could also explain how Smokey dragged Locke. Anyone who's experienced static cling knows the power of electrostatic fields. It also brings to mind the Third Policeman, in which a bicycle and its rider exchange molecules. Static cling is atoms exchanging electrons.
This could even conceivably explain the Countdown. Let's say a bigger version of Smokey is trapped behind the concrete in Swan Hatch. Perhaps entry of the Code releases the electric charge that Big Smokey periodically accumulates. Question is, what happens when its charge isn't vented...