A flight from Barcelona to Dusseldorf on the discount airline Germanwings crashed in the French Alps despite good weather, and officials say that all 148 people on board have been killed. The pilot signaled that the flight had an “abnormal situation” before the plane went down in an area that will be difficult to access. The debris has been spotted, however:

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A passenger plane crashed in southern France with 148 people on board, French officials said.

President Francois Hollande said there are “apparently no survivors.”

The passenger jet, operated by Germanwings, crashed in the French Alps region near the town of Digne as it traveled from Barcelona to Dusseldorf, Hollande said. …

Lufthansa, which owns Germanwings, released a statement on social media as reports emerged of the crash.

“We do not yet know what has happened to flight 4U 9525. My deepest sympathy goes to the families and friends of our passengers and crew on 4U 9525. If our fears are confirmed, this is a dark day for Lufthansa. We hope to find survivors,” said Lufthansa CEO Carsten Spohr in the statement.

ABC reports that tracking data from Flightradar24 shows that the plane began a descent from 38,000 to 6,800 feet, at which point the tracking on the flight was lost. The loss of altitude in the Alps would be strange, and of course deadly, as the peaks in that range go as high as 13,000 feet. The ABC analyst calls this “baffling,” making a “big descent” into that kind of terrain.

Sky News reported specifically on the “abnormal situation”:

But what does an “abnormal situation” mean? CBS News discusses what investigators will probe in the crash:

We’ll have more as events unfold.

Update, 11:30 AM: Not much more is known at this point, and even the speculation has been muted. Inclement weather will impede progress to the crash site. Meanwhile, the AP notes this tragic update from Germany:

BREAKING: German official: High school group on crashed plane; Spanish school says 16 students involved.

— The Associated Press (@AP) March 24, 2015

Update, 11:36 am: The US says that there is “no indication of a nexus to terrorism” at this time. Based on an eyewitness report, it sounds like mechanical issues might be more likely:

The owner of a campground near the crash site, Pierre Polizzi, said he heard the plane making curious noises shortly before it crashed.

“At 11.30, I heard a series of loud noises in the air. There are often fighter jets flying over, so I thought it sounded just like that. I looked outside, but I couldn’t see any fighter planes,” he told The Associated Press in a phone interview. “The noise I heard was long — like 8 seconds — as if the plane was going more slowly than a military plane. There was another long noise after about 30 seconds.”

Polizzi said the plane crashed about 5-to-8 kilometers (3-to-11 miles) from his place, which is closed for the season.

“It’s going to be very difficult to get there. The mountain is snowy and very hostile,” he said.

The municipal sports hall of Seyne-les-Alpes, 10 kilometers (6 miles) from the Val d’Allos ski resort, was being set up to take bodies from the crash, according to Sandrine Julien of the town hall.

“The plane is disintegrated,” Gilbert Sauvan of the local council told the Les Echos newspaper. “The largest debris is the size of a car.”

Hopefully the response teams can get there quickly.