Someone couldn't possibly be trying to make the crossing from Turkey to Greece in such bad weather, he thought. The rain had been coming down hard for days, and even the huge ferries that traveled between Lesbos and Athens weren't operating.
And yet now, barely visible in the glow of a car's headlights, Palacios saw them -- a man and a woman, hauling themselves out of the water, the latter falling down out of sheer exhaustion. Each of them clung desperately to a young child.
"When I tried to help her and grab the baby, she didn't let me -- but you could see something was terribly wrong," he recalls to CNN.
Palacios explains that there is a golden rule that families must never be separated. So after confirming they came together, he wanted to help get the family to a bus stop that would take them to a temporary camp nearby.
"They didn't speak English at all," says the 30-year-old Spaniard. "It was a disaster. They were throwing up, they were in shock. Somehow, with body language, they made us understand that one of their kids had fallen [in] to the water before they arrived."
After dropping the family at the bus stop, the photojournalist and some colleagues went back in search of the child -- to no avail.
"You have a family, who has just lost a baby, completely in shock, in the rain, near hypothermia and there was absolutely nothing we could do.
"That gave me the impression there were horrible days ahead. And we did."
A dire situation
That was last October -- a month which saw more than 218,000 migrants take to the Mediterranean Sea to flee to Europe, according to the U.N refugee agency
; in 2014, 216,000 people had entered Europe in the entire year.
Palacios, an award-winning photojournalist, has spent years documenting the living conditions of refugees and more recently, their journeys. He's walked the refugee trail
twice and since last September has been on the shores of Lesbos to witness the moment boats arrive.
"When I first arrived during the summer, at first view, it didn't look so dramatic," he says. "There were good weather conditions, the arrivals were kind of OK. [But] most people don't know that the place looked like a warzone. It was a warzone with out the war.
"The authorities were doing absolutely nothing. All these months, whoever wanted to go there, could go. It was a humanitarian crisis going on in a place with no control, no organization, nothing.
"During bad weather conditions, the arrivals are very dramatic. People arrive, people fall into the water. They are freezing. Kids are screaming. The children are crying. And they don't stop."
He adds: "They don't arrive to find a team of 20 doctors waiting for them. They find a few volunteers ... Many times have happened that people arrive dead. Once, a women gave birth on the beach right after disembarking. It's a really chaotic moment."
Glimmer of hope?
The haphazard scenes on the beach are a regular occurrence for Palacios, who starts his day around 5.30 am, scouting the coast for incoming boats. Once refugees have been located, he heads to their arrival point to capture the chaos on camera.
He says he usually takes a minute to read the scene, see if he can establish a visual connection with anyone, and avoids taking photos where it's clear they don't want it. He says it's about offering respect while wanting to help shed light on the crisis.
"The tool that helps me is the camera and the feeling that I'm doing something that could help. I have this feeling that somehow, not much, but somehow, after telling the story, a lot of help arrived to the place. That helps to think that it's worth it."
And the situation has improved to some extent, he says. The risk remains while the refugees are in open water, but on land NGOs have arrived and are trying to coordinate rescue boats, medical help and registrations.
"One of the problems going on right now is that there is so much noise about Lesbos -- a lot of help arrived but that didn't happen with other islands. [It's] as if this story is only happening on Lesbos, but it's not. Lesbos just has the highest numbers.
"As long as this happens, we still have to tell the story. As long as it happens, it's important. We just have to work, and work, and work, and find a way to make people empathize with that. That's our job."