“There have always been wildfires here, but never like this. It’s the first time we’ve had to evacuate,” said Mr. García, 45, who fled to Alcalá de Henares, a town on the other side of Madrid. “The worst part is the uncertainty. We still don’t know for sure whether the fire is under control. But they’ve told us it hasn’t reached the town.”

That is still more than many of the tens of thousands of other evacuees know as wildfires rage near Madrid. The authorities, trying to keep people out of harm’s way, have ordered evacuations along some routes and blocked others as firefighters struggle to contain the blazes.

Adil Mouhand Haddou and Sandra Rokosz were among those stopped by the police as they tried to return to their home in San Martín de Valdeiglesias, also west of Madrid. A police officer told them to turn back — a burning car had started a fire that was spreading into the western mountains, and the road was too dangerous to drive on. The couple pleaded to be let through, so they could rescue their two cats and their dog, but with no success.

“It’s either their lives or yours,” the officer said, according to Ms. Rokosz, 28.

On Saturday, nearly two days later, they were still being told that they couldn’t return home and were waiting in their car for news about their home and animals. “We know nothing — whether they have asphyxiated or whether a neighbor rescued them by chance,” Ms. Rokosz said.

The evacuations have affected a wide region around the Spanish capital, casting dense smoke over cities, plumes that have prompted official orders for many residents to stay indoors and out of the choking air.

“I only remember smoke and ash falling from the sky,” said Gaël Kaisergruber, 18. He woke up on Friday thinking he would never have to flee; a few hours later, as wildfires closed in, he was packing family photos, clothes and important documents, to flee his home in Colmenar del Arroyo.

His parents, who were vacationing in northern Spain, called and told him to leave with his sister, even before the authorities issued an evacuation alert. He and his sister reached their parents, learning from the authorities later that although their own home was safe for now, some on their town’s outskirts had burned down.

“It’s all so sudden, you can’t even think,” he said.