They came in waves of hundreds, rowdy music fans crashing against the barrier fences surrounding the main Bluesfest stage Thursday night.

When security guards tried to push them back, the packs of mostly young people started hurling rocks.

Even seasoned security experts said they've never seen anything like it in Ottawa.

We almost need to teach the public how to parent their kids now. They're like animals. - Chris Ibey, Toersa Security Inc.

"This is the first year that we've seen them all coming together in big groups," said Chris Ibey, president of TOERSA Security Inc., the company hired by Bluesfest organizers to control crowds at the 11-day music festival.

"We had one security guard who took a rock to the forehead. We almost need to teach the public how to parent their kids now. They're like animals."

On Friday Ibey's security team was in contact with police and city officials to discuss how to move forward over the remaining three days of the festival.

Fences that were pushed over Thursday have been reinforced and topped with spikes.

"In terms of prevention, I think we're doing as much as we can," said Ibey.

Chris Ibey, president of the security company hired by Bluesfest to control crowds, said some Bluesfest patrons acted 'like animals' at Thursday night's concerts. (Ashley Burke/CBC News)

Crowd out of control

A big part of the problem, according to Ibey, was that people were showing up to the venue already drunk. Paramedics and their partners dealt with 200 cases Thursday night, or a new patient every 90 seconds.

"I was amazed at how well our people did," said Nick Cartwright, a special events patrol leader with the Canadian Ski Patrol, which provides first aid at the event. "When people want to create trouble it's really hard to deal with them."

In a statement, Peter Kelly, deputy chief of the Ottawa Paramedic Service, said paramedics are adjusting staffing levels for the remainder of the festival.

Katelynn Shoniker, a food truck worker who was at the festival Thursday, said the crowd was out of control.

The fences surrounding the Bluesfest stage at the Canadian War Museum have been reinforced after rowdy mobs tore some down Thursday night. (Ashley Burke/CBC News)

"It was one of the wildest crowds Bluesfest has had in a while, it was non-stop," she said. "Nobody knew how to contain themselves and no one had any respect."

Shoniker said she witnessed one girl get attacked, and watched friends nearly get trampled by a mob.

Ottawa police said they dealt with a number of intoxicated festivalgoers Thursday night and arrested two people who were released without being charged.

Rowdy night a one-off

Thursday night was "a challenging situation," a Bluesfest spokesperson said in a statement Friday.

"Bluesfest organizers are not anticipating the same level of demand for emergency services this weekend, and will be well prepared in any event," the release continued.

According to Bluesfest, staff will be reviewing protocols ahead of next year's festival.