The situation with people trapped in the Sinjar mountains .....

and those who have managed to escape and cross the border into Syria.

Here's what happening to the Iraqi Yazidis, Kurds and Christians trapped in the mountains.  If there are any Iraqi Shiites too trapped up there with them or in flight, that's not clear at this point.

From TelegraphUK:
At least 300 people, mostly children, died
on Mount Sinjar, say doctors
At least 300 people, most of them children, died whilst trapped on Mount Sinjar, doctors have told The Telegraph.
As the last few hundred refugees finally received aid or reached the relative safety of camps in Syria and Iraq, families have begun to take stock of their terrifying ordeal.
Up to 150,000 people fled when Islamic State militants and their allies stormed the Iraqi city of Sinjar, and then suffered a gruelling journey over mountain peaks, some walking for days, without food or water, in blistering temperatures......
........Up to 70,000 people passed through Nawrouz camp in Syria, the first place for them to rest and receive aid after the hundreds of miles travelled to get off the mountain.
Under mismatched tents or tarpaulin sheets they tried to catch some rest and rehydrate. Most then travelled on to return to Iraq via a crossing that brought them to a safer part of the country, north of Mount Sinjar. They make up an estimated 1.2 million people who have been internally displaced since the Islamic State took control of Mosul in June.........

From WHO:
WHO responds to health challenges facing people trapped on Iraq’s Mount Sinjar.  
The World Health Organization is supporting the delivery of urgently needed health services to people affected by insecurity in northern Iraq, including tens of thousands of children, women and men trapped on Sinjar Mountain and many more who have escaped to safer areas.

“The health situation on Sinjar Mountain is precarious for approximately 50 000 people believed trapped there, while 60 000 more who have crossed the FeshKhabour border-point through Syria to enter back into Iraq at Dohuk,” said Dr Jaffar Hussain, WHO’s Representative to Iraq......

......At the Iraqi-Syrian border point of Feshkhabour, 16 ambulances, two medical doctors and 10 paramedics are providing health services.
In addition, WHO, in conjunction with the Iraqi Ministry of Health and UNICEF , is undertaking a five-day polio vaccination campaign across the country, with the aim of immunizing 4 million children aged under 5 years in 12 governorates against the crippling and incurable disease. The immunization drive was launched in Dohuk on Sunday.

WHO is working on providing the Ministry of Health with US$20 million worth of medicines to be distributed in the areas with a high influx of displaced people. .........

From NYTimes:
Despite U.S. Claims, Yazidis Say Crisis Is Not Over
Yazidi leaders and emergency relief officials on Thursday strongly disputed American claims that the siege of Mount Sinjar in northern Iraq had been broken and that the crisis was effectively over, saying that tens of thousands of Yazidis remained on the mountain in desperate conditions.....

.....Speaking from her hospital bed here, Vian Dakhil, an Iraqi member of Parliament and a Yazidi leader who was injured in the crash of a helicopter delivering aid to the mountain on Tuesday, said she was aware of the American claims and had discussed them with Yazidi leaders still in the area.
“It’s not true,” she said.
“It’s better now than it had been, but it’s just not true that all of them are safe — they are not,” Ms. Dakhil said. “Especially on the south side of the mountain, the situation is very terrible. There are still people who are not getting any aid.”
She estimated the number of Yazidis trapped on the southern flanks of Mount Sinjar at 70,000 to 80,000.........