The same devastating crown fire burned forest on both sides on the Lewis River Canyon. Shooting firebrands far in advance of the flame wall, the wind-whipped blaze leaped this 500-yard-wide natural barrier.

The scene puts human-made barriers—roads, bulldozer lines—in perspective. Even the most resourceful firefighting crews cannot control fires of this magnitude.

At Yellowstone, regeneration is at least as powerful a force as wildfire. Every 200 to 400 years, fires as catastrophic as the 1988 blaze have swept across the plateau—yet the vegetation and wildlife have thrived.

1. High winds sweep a ground fire into a hot crown fire, consuming entire trees.

2. Embers, carried aloft by rising flames, may ignite "spot fires" miles ahead of the main blaze.

3. "Spotting" allows a fire to jump major barriers.