Update 2007.10.24: NASA continues to publish updated satellite imagery of the fires and the natural phenomena driving them. Check the sidebar of their page for “Other Images for this Event”.

By Wednesday morning, 600,000 people had been displaced by the fires. By the afternoon, CNN upped the estimate to over 900,000.

Image acquired 2007.10.22 13:55 PDT

Watching the news this morning before going to work, I was shocked to hear that a quarter of a million people – 250,000 – have been displaced by the fires in California. This satellite image, taken less than 24 hours ago, provides some sense of the scale of what’s going on there.

In what seemed like the blink of an eye, wildfires ignited in the paper-dry, drought-stricken vegetation of Southern California over the weekend of October 20, 2007, and exploded into massive infernos that forced hundreds of thousands of people to evacuate their communities. Driven by Santa Ana winds, fires grew thousands of acres in just one to two days. The fires sped down from the mountains into the outskirts of coastal cities, including San Diego. Dozens of homes have burned to the ground, and at least one person has died, according to local news reports. Several of the fires were burning completely out of control as of October 22.
…
The drought in the Southwest throughout summer 2007 has been “extreme” according to the categories used by the U.S. Drought Monitor. Dry vegetation and Santa Ana winds, which can reach hurricane force as they race downslope from the deserts of the Great Basin and through narrow mountain passes, are often a devastating combination in Southern California. According to the Incident Management Situation Report [PDF] from the National Interagency Fire Center for October 22, Santa Ana winds were expected to continue through Wednesday.

– Fires in Southern California, NASA Earth Observatory

Links
California Fire News (Blog)
CNN Coverage
NASA: Fires in Southern California