It had been burning in Berlin's Grunewald for more than twelve hours when the good news came for operations manager Thomas Kirstein in the late afternoon. The police explosives expert allows the firefighters to come within 500 meters of the scene. Before that, they had to stay a kilometer away from the detonation site in the middle of the West Berlin forest area, where 50 tons of ammunition from the Second World War are still stored. So far, the risk of further explosive devices detonating and people being injured during extinguishing was too great.
This is what makes the mission so difficult for the more than 500 emergency services from the fire brigade, the German armed forces, the Federal Agency for Technical Relief and the police. You must extinguish a forest the size of two football pitches and prevent the fire from spreading without being able to get to the hearth itself. Helicopters are not a solution, because the pressure wave emanating from possible further explosions reaches up to a height of 1000 meters in the air. If the helicopters fly higher, the water would evaporate from that distance.
So the Bundeswehr cuts aisles in the forest, the fire brigade waters the surrounding forest, while the commanders try to get an idea of what is going on in this one-kilometer exclusion zone. Drones deliver aerial photos of the blast site, a robot helps with soil analysis. On this basis, the police explosives expert finally decides on the danger situation and agrees that firefighters can come as close as 500 meters.
And so Kirstein can give the all-clear for the first time after twelve hours of use at 36 degrees and in the blazing sun. The fire brigade operations manager even expects the situation to be under control on Friday night. The last explosions were heard at noon. "Every additional minute that we don't hear a detonation is good," says the spokesman, who has been patiently explaining every detail of the operation to newly arriving journalists for many hours, while water cannons and fire engines drive into the aisle to the forest with a loud roar.
Kirstein himself was awakened at 4 a.m. by the first explosion in the Grunewald near the Brandenburg border, which could be heard in the surrounding districts of Berlin. The fire brigade had already been deployed about an hour earlier to put out a fire, without realizing that they were in grave danger.
Because more ammunition exploded at the blast site, the firefighters later reported to Kirstein that human-sized debris flew past them. It then became clear that this fire was no ordinary one, that the flames could not simply be extinguished, that the police and the armed forces needed help to protect the lives of the firefighters, but at the same time to prevent it from spreading.
The cause of the fire was not known as of Thursday evening. It's not even clear if one of the explosive devices started the fire and if so, how it could have happened - because the eight-hectare facility is tightly secured. It is also possible that the fire first broke out in the forest and then spread to the camp.
The police are investigating in all directions, says police spokesman Thilo Cablitz. And thus also takes up the question of how it can happen that a blast site in the Berlin city area became a danger zone. At no time were residents in danger, he emphasizes. "And of course the decision was made to create such a place in the forest and not in the city."
The area is secured by the police and not accessible. There has never been an incident since it was built in the 1950s. Twice a year, the police blow up old ammunition there in a controlled manner - the next date for this is not until autumn. Governing Mayor Franziska Giffey (SPD) announced in the afternoon that she would have the ammunition site checked in the future.
The Berlin fire brigade is preparing to stay longer. It could be several days before the last embers are gone. It is not yet clear how many of the 50 hectares of forest have been burned - many areas are only covered with smoke.
Operations manager Kirstein is optimistic in the late afternoon that 30,000 additional liters of extinguishing water could be obtained. But in the evening there are more explosions. A special robot from the Bundeswehr was supposed to explore the blast site when detonations were heard. The mission was therefore canceled, says Kirstein. There were several more detonations afterwards.