Given who God is and things like God's warning to Moses ("no one can see me and live") - not to mention our own ideas about God - when God passes by Elijah, we are expecting it to be something literally awe-inspiring (and maybe even deadly).
When something or someone is a big deal, there's usually a special introduction to tell us just that. Every four years, the Olympics start with an opening ceremony (often bordering on the ridiculous) in a stadium full of floats, lasers, costumes, props, people, music, fireworks, etc. Every week professional wrestlers get lightshows and indoor fireworks when they are introduced.
So it's more than a little surprising that, after all of the "fireworks" (rock-crushing windstorm, earthquake, firestorm), God shows up not in something that one-ups the fireworks - but in the still small voice afterwards.
It's not what we expected, and it tells us a lot about God that we could never hear during the fireworks.
More on Sunday's readings tomorrow. Readings for the 19th Sunday in Ordinary Time: http://www.usccb.org/bible/readings/081014.cfm