FALLBROOK, Calif.  — Flames were practically on top of Dick and Joan Marsala’s home when they got an urgent knock on the door and were told to leave.

The couple, in their mid-80s, grabbed only a change of clothes and medications before fleeing Thursday through wind gusts and smoke as fire swallowed the row of mobile homes behind their place in the Rancho Monserate Country Club north of San Diego.

It’s a story that has played out in communities across much of Southern California this week as ferocious winds whipped sparks into massive infernos that have destroyed more than 500 buildings, killed dozens of horses and forced hundreds of thousands of people to run from fires that have burned nearly 250 square miles since Monday.

The flames that tore through Fallbrook, self-proclaimed “Avocado Capital of the World,” and nearby Bonsall, home to a premier racehorse training facility, traveled so far that even people who found temporary refuge had to move again when the fires got too close.

Flames sprang up so quickly and moved so fast that three people were burned Thursday trying to escape. Many of those who managed to get out unscathed did so with only the clothes on their backs.