At al-Hawl, an overwhelmed displacement camp for the wives and children of Islamic State fighters, women in niqabs scream at each other. Small children and babies lie unattended on the muddy ground: one boy, no more than two years old, is clearly in a feverish sleep.

Children with no shoes walk on the dirty nappies and other rubbish that litters the area. The smell of human waste is overpowering. As Isis makes its last stand in Syria’s eastern desert, this is the group’s legacy.

The women who joined Isis are not sympathetic refugee characters, and as the fight to destroy the “caliphate” nears its end in the town of Baghuz, those leaving have become increasingly defiant. In recent days, many woman said they only left because the group’s leader, Abu Bakr al-Baghdadi, ordered them to do so to make it easier for the men to fight.

Until this week it was home to Shamima Begum, who left east London with two schoolfriends in 2015 to join Isis, but was moved to another camp near Derik along with all the other foreign nationals, the Hawl authorities said.

Al-Hawl camp was the home of British teenager, Shamima Begum until she was moved to another camp last week. Photograph: BBC News

As tens of thousands of women and children continue to pour out of the tiny area still under Isis’ control, local authorities say they have reached a breaking point and the families of the caliphate – around 43,000 new arrivals in al-Hawl alone – are at the centre of a humanitarian crisis.

Most of those suffering here are children. The UN and International Rescue Committee say at least 80 people, two thirds of them under the age of one, have died since December, when the camp began to see a huge influx of those fleeing the violence.

About 2,000 people are sleeping outdoors in the screening area this week despite the rain and winter temperatures as the camp’s management struggles to process new arrivals.

“This is an extremely vulnerable population,” said Paul Donohoe, an IRC spokesperson. “They’ve been without medical care and adequate food and water in some cases for weeks, which is contributing to why so many are dying on arrival. There’s also an astonishing number of pregnant women. Some have been giving birth on the trucks that bring them to Hawl.”

The chaos is evident. In al-Hawl’s transit area, children wander around calling for their parents, some from central Asia and Africa. A Yazidi boy is plucked from the mayhem and taken to the camp’s office. He says he is from Sinjar in Iraq but he doesn’t know who brought him to al-Hawl or where his family is.

Tens of thousands of women continue to leave the area still under Isis control. Photograph: Delil Souleiman/AFP/Getty Images

The camp’s management fears the outbreak of dysentery.

“Providing medical care and hygiene to everyone in the camp is almost impossible,” said Sozdar, a camp security officer.

“Our resources are very limited. Some of the international aid agencies say they have not reached us because the road to the camp is not safe,” she added.

The volume of people coming out of Baghuz and the lack of planning also raises questions over the quality of the US-led coalition against Isis’ intelligence operations, said Donatella Rovera, Amnesty International’s senior crisis response adviser.

“Adequate air or remote surveillance will reveal civilian movement,” she said. “There have already been serious underestimates of civilian presence in operations against Isis in Raqqa and Mosul.”

Tensions among al-Hawl’s residents are running high as a result of the appalling conditions. Several women told the Guardian that senior-ranked wives in the camp have set about recreating Isis’ strict rules, stealing the belongings or beating the children of women who take off their niqabs.

A Syrian woman waits with her child at a makeshift clinic at al-Hawl. Photograph: Fadel Senna/AFP/Getty Images

A fire caused by a leaking gas canister earlier this week – a regular occurrence in refugee camps – also sparked rumours that it had been set on purpose by an Isis sleeper cell attempting to free those inside.

“The lack of preparation for what comes after Isis is shocking,” said Nadim Houry, the director of Human Rights Watch’s terrorism and counterterrorism programme.

“In almost all the areas retaken from Isis, there is not adequate resources to rebuild or protect people on the ground. It is extremely worrying for these children who haven’t gone to school in the caliphate. They are very vulnerable and without a real education and support, radicalisation is going to continue to be a problem.”