“Paradise is an old, wooded town with narrow surface streets — and it’s a retirement community,” said Scott McLean, the deputy chief of Cal Fire. The ferocity and speed of the flames were breathtaking, he said. “The winds were phenomenal, pushing everything down across the roadways. Roads were simply blocked. People ran out of gas. It was an accumulation of everything all at once.”

[Follow live updates on the fires from our reporters on the ground here.]

Seven people died in their cars in Paradise. The blaze was so hot that aluminum wheels melted, as they did last year in Santa Rosa during the Tubbs Fire.

In an article published Sunday, we examined how the trauma of the fire was compounded by the difficulty of escape. There was only one main road leading out of Paradise when the fire started on Thursday morning, and it quickly became swamped with traffic. As wildfires in California become larger and more intense, our story raises the question of how many other towns in the state have a similar vulnerability.

Evacuation planning was not an oversight in Paradise. The mayor, Jody Jones, worked for years as a regional manager for the California Department of Transportation. Traffic management is her specialty. The town held evacuation drills.

Ms. Jones worries that no amount of planning could have prevented the panicked gridlock in Paradise.