Ruth Sherlock

Updated at 3:25 p.m. ET.

Thousands of Syrian refugees have been forced from their tents in Lebanon, following days of bitter rain, snow and freezing temperatures. The winter storm, dubbed Norma by Lebanese meteorologists, has left refugees in dire need of emergency assistance, aid workers say.

The al-Hol refugee camp, in northeastern Syria near the border with Iraq, is overwhelmed with new arrivals. For years, the camp, run by Kurdish authorities with help from the United Nations and other international organizations, has housed thousands of Iraqi refugees. More recently, though, the camp has become home to large numbers of Syrians, fleeing towns where the U.S.-led coalition is fighting the last remnants of ISIS. Hundreds of thousands have become internally displaced, with many families forced to move multiple times.

Syria's army is grouping at the outskirts of Manbij, a hotly contested town near the Turkish border, in a move that is apparently coordinated with the pending withdrawal of Kurdish militants who have long held the city.

The news comes after initial media reports suggested that for the first time in six years, Syrian troops had taken control of the northern city. Manbij is occupied by both the U.S.-backed Kurdish YPG and American troops.

In a classroom that's so cold you can see your own breath, five teenage girls, their hair covered by brightly patterned scarves, and two boys read English phrases from textbooks. Repeating after their teacher, they say, "It has plants from all over the world."

The lesson, about an indoor rainforest in the United Kingdom, is a world away from the devastation surrounding them. They are students in Raqqa, Syria, a city that ISIS once claimed as its capital.

The green landscape of rural northeastern Syria is home to wild ducks and donkeys, villagers tending cattle — and U.S. military bases housing 2,200 troops. American soldiers patrol the countryside in armored vehicles and hover overhead in Black Hawk helicopters. In the Kurdish-majority area known as Rojava, towns are bursting with Christmas decorations. Holiday lights adorn almost every main street in the city of Qamishli, whose diverse population includes many Christians, and shops are selling tinsel and plastic trees.

Um Mohammed says she was in search of a happier life when she decided to bring her family from the Netherlands to live under ISIS.

"I thought the ISIS 'caliphate' would be perfect, like a utopia," says Um Mohammed, who describes having felt discriminated against as a Muslim in the Netherlands and says the militant group's online propaganda drew her in. "I don't think [life in the caliphate] was what most people expected. I regret going and having, you know, to go through this."

Editor's note: This story contains descriptions of dead bodies.

On a busy street corner in Raqqa, Syria, a digger pushes through the rubble of a building hit by an airstrike. Onlookers shield their mouths and noses from the dust and stench of corpses of those who perished beneath.

Just streets away, three recovery workers pull out the delicate skeletons of two children from under the debris of a partially collapsed home. And across the city, in what was once Raqqa's public park, men unearth more bodies from a mass grave.