Hiker missing in Isola: how a drone helped locate the victim

The search for the snowshoe hiker, missing since Sunday in Isola, ended tragically. The unfortunate woman was found deceased. Originally from Nice, she was 52 years old.

State-of-the-art technology comes to the rescue for victim searches. On Monday, a drone helped locate the body of a snowshoe hiker who had gone missing in the Isola 2000 area. The unfortunate woman was found in the bed of the Chastillon valley stream, not far from Pélevos head. On Sunday, after the alert was raised by the family, who had not seen her return, the rescue teams were quickly hindered by darkness.

Beyond the darkness, the commander of the rescue operations, Boris Poix, who leads the CRS Alpes, was faced with a common problem in the mountains: finding the hiker in a steep, difficult-to-access area. “At that moment, it seemed to me that the drone was the most suitable tool to help us in these searches.”

Until recent years, these devices have not always been very effective in the mountains. And that’s for a simple reason: autonomy. “The technology has evolved a lot. Before, due to the cold, the drones only had five minutes of autonomy. By the time the operator positioned themselves with a correct visual, it was already time to return because the batteries did not hold up. Today, the drones can not only resist for twenty minutes, but they also withstand winds of 30 km/h. Wind needs to be taken into consideration at altitude. And the resolution is stunning.” The waterproof device can fly in the rain. The model used is a DJI Matrice 30T, equipped with three lenses (zoom up to 200 times in digital), capable of searching for a person or reading a license plate at a distance of 500 meters.

A delimited area thanks to telephony

This Sunday, as the first “classic” searches proved unsuccessful, the professional drone operator of the national police was placed on pre-alert. “It is important to know that using a drone, without knowing where the victim is, that is to say, without delimiting an area, is useless,” explained Commander Poix. “We worked at night to delimit an area.” Telephony was a great help.

The geolocation of the victim’s mobile phone, which had stopped transmitting in the middle of the afternoon, was requested from Apple. “This geolocation allowed us to accurately target the search location. From the last known point, and from the moment she did not return to her car, it was clear she was in a difficult area. Next to it is the Chastillon stream, a deep ravine.” Ground searches were interrupted around 3:30 in the morning.

This Monday morning, armed with this information, the police drone pilot was mobilized. “In these cases, we set up an advanced command post for the drone pilot. He is not a mountain specialist, so we transported him to the site. The pilot works in pairs with a mountaineer from the CRS Alpes. “Mountain flying is different from urban areas. Our drone pilots are mainly trained in urban areas, but we train with them sometimes.”

The victim was in the bottom of a deep valley

Equipped with a very high resolution camera, the drone can cover areas extremely difficult to explore on foot. “In this search, I had patrols out. But they passed by without seeing her. The victim was dressed in black and was in the bed of the Chastillon stream, very difficult to spot from the ground. The drone was really useful in this case.”

The DJI Matrice 30T carries a thermal camera. A similar model had been used to locate a missing person in Grenoble. This is not live observation of “hot spots”. The drone returns to its base, and it is at that moment, analyzing the images, that the operators identify points of interest and send the drone back for a visual, non-thermal observation this time. “But in this case, it was impossible. In winter, at minus ten degrees, next to a very steep stream, the thermal camera was inoperative.”

This Monday, when the police drone operator took off, he quickly identified the snowshoe tracks of the missing woman in the snow. “He followed them with his device. He is able to do that, even under trees, with an angle that allows him to spot them. It requires great skill.”

When the drone finally found the victim, the CRS Alpes could only observe that it was unfortunately too late. A moment always difficult for these mountaineers. But being able to return a body to a family is an extremely important mission, in the mountains or elsewhere.

A ground convoy was then sent to the site. The victim was placed in a stretcher by the mountain specialists. Her body was hoisted by the Dragon 06 helicopter of the civil security.

It is clear that drones are increasingly seen as an essential technique in the array of mountain rescue possibilities. The same as helicopters or land searches. “In the future, we can imagine a combination with a drone carrying a loudspeaker broadcasting the name of the victim, with a recorder capable of keeping track of a human voice. There is also already an artificial intelligence capable of discriminating a human form. This system is not authorized, but it would make it easier to find a shape that would escape the human eye.”

Commander Poix, however, emphasizes that technology alone is not enough. “The drone makes sense when it is used with humans, and not by itself.”

La CRS Alpes a envoyé un drone sur place. (Photo DR)

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