[UPDATED 2014-05-20 1835 UTC] Amateur Radio volunteers in Serbia have been putting in long hours supporting rescue operations in the wake of unprecedented flooding in the Balkans that has affected Serbia, Croatia, and Bosnia-Herzegovina. Meteorologists have called the flooding the worst that Serbia has experienced in more than 100 years. The death toll stands at more than three dozen. CNN reported that 13 bodies had been recovered in the town of Obrenovac, Serbia, where radio amateurs have been coordinating communication to boat crews that are rescuing stranded residents. Alliance of Serbian Radio Amateurs (SRS) member Nenad Supurovic, YU1TTL, deployed to Obrenovac, after registering with the crisis center, to support communication between rescuers and emergency managers keeping track of those needing to be evacuated.

“We showed our radio transmitters, and [the police] immediately let us through, as if we were ministers of state,” Supurovic told AlJazeera in an interview. “Nobody welcomed us. We went and reported to the radio amateur just finishing his shift. There were four of us.” He said the hams have been able to provide “an alternative link” to the rescue crews. The crisis center sends addresses of people who needed to be evacuated, and the Amateur Radio volunteers tell the rescue boat crews where to go next. Each boat has a local resident aboard, who knows the town and can direct the vessel to the right location — in some cases, even though flood waters already have obscured street names and house numbers.

Marijan Miletic, S56A/N1YU, who has been observing the flood situation from Slovenia, told ARRL that radio amateurs in Serbia and Bosnia have activated emergency networks in the flooding’s aftermath, and Tilen Cestnik, S56CT, was dispatched to the affected region to assist. He said Croatia was not as badly affected as Serbia, and that there has been a lot of mutual aid among the former republics of Yugoslavia. Miletic said Zoran Mladenovic, YU1EW, was heading up the headquarters operation in the Serbian capital of Belgrade, with the help of a 2 meter repeater with a wide coverage area. Belgrade is at the confluence of the Sava and Danube rivers and could see flooding later this week.

SRS member Dragan Antonic, YU1UO, predicted that Amateur Radio volunteers will be active through the end of the month. He’s been working at an emergency operations center in Belgrade, and he estimated that hams already have handled some 25,000 pieces of traffic.

“Our equipment, our people, and our knowledge are used to pass…information to the rescue people,” he explained in an interview with Kristina Kukolja of SBS World News. He said the radio communication helps the crews in the field to be more efficient in locating and evacuating those in danger. The ham radio volunteers, he told Kukolja, will be on the scene “for as long as it takes.”

An estimated 24,000 people have had to be evacuated to safety in Serbia, while another 30,000 people were displaced in Bosnia-Herzegovina. As sometimes happens in similar situations, a few residents refuse to evacuate, because they don’t want to leave their homes.

CNN quoted a statement from the Serbian Embassy in Washington over the weekend, which said that many towns and cities in western Serbia “are completely underwater,” describing the situation as an “unimaginable catastrophe.”

Supurovic said that by and large the people who were evacuated appeared to be in good condition. “At the beginning it looked like they were just really tired,” he told AlJazeera, “like they’d spent the whole day on public transport.”