For weeks, as many as 40,000 Iraqi civilians were reportedly stranded on Mount Sinjar in northern Iraq after fleeing the brutality of the Islamic State's steady advance. They were hungry, thirsty, and exposed to extreme temperatures. The Obama administration could not avoid responding to the mounting humanitarian crisis.
As the White House planned a series of airdrops and a flurry of airstrikes to keep the Sunni militants at bay, President Barack Obama, loathe to intervene militarily in the region, seemed to use the trapped Yazidis as justification for a bombing campaign in a country from which he had proudly removed all U.S. troops in 2011.
But then came a surprise: After inserting a small military reconnaissance team atop the mountain, Defense Secretary Chuck Hagel said late Wednesday that the situation was no longer as bad as anyone thought. There are now only about 5,000 civilians on the mountain, and they are in "better condition than previously believed," according to Hagel's statement.
For roughly 2,000 of those civilians, mostly from the minority Yazidi religious sect, Mount Sinjar is home and they do not intend to leave. Now it seems the dire situation has improved and that focus is shifting to refugee camps in Syria and Iraqi Kurdistan.
The question now becomes how the Pentagon's expansive, weeklong surveillance mission over northern Iraq -- as many as 60 manned and unmanned air "sorties" per day -- apparently gave the United States government highly inaccurate information.
On Thursday, Obama said the proposed rescue mission was off, as it was no longer necessary. And the humanitarian airdrops, which began a week ago, could also wrap up. Administration officials are now mulling how they'll approach Iraq's security and humanitarian situation going forward.
Pentagon spokesman Rear Adm. John Kirby tried explaining why initial reports were so off, saying that the situation had improved greatly, mostly thanks to the U.S. military. The U.S. bombing campaign allowed thousands of the desperate civilians to descend the mountain -- as many as "thousands per night," he said Thursday.
The Pentagon stands by its initial estimate that "tens of thousands" of civilians were trapped. However, the assessment team's arrival on the mountain was crucial to understanding the scale of the crisis, Kirby said.
"It's very difficult to do nose counts from the air.... I mean, it's just an imperfect science," Kirby said.
Persistent surveillance flights do not give "perfect" situational awareness, he said. The Pentagon estimated the best it could from the air, knowing that getting a clearer picture required deploying a team, he said. That fewer Yazidis were in desperate need of help than originally thought is "a pretty good thing to be wrong about," Kirby added.
Using drones and satellite imagery, the National Geospatial-Intelligence Agency made initial refugee estimates for the United States. Getting a firm head count was impossible because the refugees were constantly moving around the mountain and entering and exiting scattered tents, putting them beyond surveillance capabilities, according to U.S. officials.
"Experts don't think [initial estimates] were inaccurate in retrospect," a U.S. official said. "It was that the situation improved more quickly than perhaps we had thought."
But air-surveillance experts say the Pentagon should have been able to estimate more accurately how many people were still on the mountain.
"It's a bit of a surprise that there was that degree of uncertainty," David Deptula, a retired Air Force three-star general who was the chief of staff for the service's Intelligence, Surveillance, and Reconnaissance headquarters, told Foreign Policy.
Drone operators typically feed pictures to intelligence analysts on the ground who could use them to determine roughly how many people are in an area under surveillance -- and, in this case, how many might be leaving. Most ISR aircraft can discern between a couple of thousand people or tens of thousands of people, said Deptula, now the dean of the Mitchell Institute for Aerospace Studies in Arlington, Virginia.
"It's pretty straightforward: You survey the region that you're interested in over a period of time, then you count the number of people who are there," he said. "It's not rocket science."
It's possible that if intelligence analysts saw the refugees fleeing the mountaintop, defense officials would not tell the public for fear of making those civilians targets. However, the Pentagon did not hint that it was aware of any migration until the reconnaissance team landed on Sinjar.
Karwan Zebari, a representative of the Kurdistan Regional Government in Washington, said upwards of 40,000 people were stranded at one point.
He said 240,000 people fled Sinjar and its surrounding towns, with roughly 200,000 finding immediate safe haven in Iraqi Kurdistan. The rest fled to Mount Sinjar, a range of peaks stretching roughly 45 miles.
Some Kurdish Peshmerga forces, who were able to repel Islamic State militants with the help of U.S. airstrikes, were among the stranded civilians.
Starting about three to four days ago, thousands of the Yazidis began finding safe passage by briefly escaping into Syria and then crossing back into Iraqi Kurdistan via the Semalka/Peshkabour border crossing. The trek is roughly 25 miles. Some families walked up to 15 hours a day to make it to safety, Zebari said.
According to the U.N. refugee agency, people are arriving in Syria weak and traumatized.
"Their feet are covered in blisters, having spent days on Mount Sinjar in searing temperatures without food, water or shelter after fleeing for their lives, then walking many hours -- in some cases days -- to find safety," according to a statement from the U.N.
Mirza Ismail, the head of the Yazidi Human Rights Organization, a network of Yazidi groups in the United States and Canada, has spoken to the decamping Yazidis by cellphone. U.S. airstrikes were crucial to keeping advancing Sunni militants at bay while his countrymen escaped, he said. "Authorizing airstrikes and sending humanitarian aid saved thousands and thousands of Yazidis."
However, Ismail disputed the statement made by Obama on Thursday that "the situation on the mountain has greatly improved," and that there were fewer stranded Yazidis than many anticipated.
"We need more help," he said, estimating that thousands of Yazidis remained stranded on Mount Sinjar -- a view bolstered by Kurdish officials who spoke with the Washington Post.
From the moment President Barack Obama announced the mission to help save the Yazidis stranded on the mountain, his administration seemed unsure about how many people were trapped up there.
"Thousands -- perhaps tens of thousands -- are now hiding high up on the mountain, with little but the clothes on their backs," the president said Aug. 7.
Four days later, on Monday, the number remained up in the air. At the Pentagon, Lt. Gen. William Mayville said he'd seen a range of numbers. "I've seen reports of numbers in the thousands, and I've seen reports in the numbers of tens of thousands."
He added that an on-the-ground assessment would be needed before the military could recommend the next steps to be taken.
In the meantime, pressure was building for the United States to take further action and begin an evacuation mission. The U.N. estimated that 40,000 people were stranded, including 25,000 children.
On Wednesday, White House spokesman Ben Rhodes said the White House was looking at options for an evacuation mission, including using U.S. military aircraft to deploying ground troops to help establish a safety corridor.
As for how many people were still on the mountain, he also kept it vague, saying, "We believe that some number of thousands of people have been able to escape from the mountain, but not in a safe enough way and to a safe enough space that we're confident that the remaining people who are trapped there can get off."
Later that night, everything seemed to have changed. The Pentagon announced that its team had assessed that there were far fewer Yazidis on Mount Sinjar than previously feared.
The president ruled out the need for an evacuation plan.
Still, Kirby left the option open of future humanitarian airdrops if needed, and emphasized that the threat from the Islamic State was far from eliminated. "It's not like we're sitting here just breathing a sigh of relief now because everything is better -- or things look to be better on Mount Sinjar."
John Hudson and Yochi Dreazen contributed to this report.
AHMAD AL-RUBAYE/AFP/Getty Images