(CNN) -- When gunfire erupted at Marjory Stoneman Douglas High School in February, paramedics sped toward the school, sirens blaring. As they got closer, the magnitude of the carnage became evident.
The streets were packed with police cars and ambulances, some blocking the roads. The shooter's whereabouts remained unknown, adding to the chaos and uncertainty.
The Coral Springs-Parkland Fire Department released audio recordings Thursday that show first responders scrambling at the scene of shooting that left 17 people dead.
"This is going to be a big event," a fire department commander told a dispatcher. "And see if I can have somebody contact all the area hospitals. Just let them know that we have an incident and we may be sending patients in all directions, so they should start preparing for it."
The Coral Springs-Parkland Fire Department released the documents at the request of several journalism outlets, including CNN.
Here are the key points from the recordings:
Some rescuers couldn't get to the school
Dozens of police cars and ambulances descended on the Parkland, Florida, school. At some point, some vehicles were blocking others.
"It's an absolute mess, absolutely nuts," a rescuer told a dispatcher. "It is completely closed down. PD needs to close down everything from Sawgrass (Expressway) north because there is no movement there whatsoever."
"It's absolutely... it's a zoo," he added.
Parents raced to search for students
Law enforcement officers were searching for the shooter, not knowing if he was still armed or in school grounds. Paramedics were loading ambulances, trucks and even golf carts with gunshot victims. Some parents were searching for their children.
"If anyone is in contact with PD, we are going to need a perimeter around the school. We have parents running in the building," a commander told dispatch.
Agencies could not communicate among each other
Law enforcement officers from two different agencies descended on the scene and discovered their radios didn't work correctly. The fire department could not communicate with them, either.
Police officers were calling rescue workers directly because they couldn't get through dispatch, a dispatcher said.
The Broward County Sheriff's Office had said their radio system "can become impaired when an excessive number of users access the system."
Dispatchers were frustrated
A dispatcher became frustrated when they could not get information from law enforcement.
"Here's the situation," a dispatcher told a rescue worker. "Broward County is handling this. They have not relayed any information to us where the command post is. We've been attempting to get this information repeatedly and do not know."
Manhunt prevented rescue helicopter from helping injured
A rescue helicopter initially responded to the shooting when several rescuers requested airlifts. With law enforcement still looking for the shooter, paramedics could not risk it.
"I'm being asked where you guys would like the landing zone for the trauma hawk," a dispatcher asked.
"We can't put the bird down yet due to an active hazard," a commander replied.
It's unclear where the helicopter eventually landed near the school.
™ & © 2018 Cable News Network, Inc., a Time Warner Company. All rights reserved.