The massacre in Las Vegas last Sunday has forever changed the way concert organizers and security experts think about outdoor shows and events.
Before Stephen Paddock opened fire on the outdoor Route 91 Harvest Festival with an arsenal of guns rigged to fire like automatic weapons from the 32nd floor of the Mandalay Bay resort, security mainly involved pat-downs and metal detectors as concert-goers entered.
Now, they have to ask: Where could someone shoot from? Where are the exits and are they "fatal funnels?" How can first responders get to casualties?
"We need to think outside the box to cover every eventuality and scenario that can happen so that what happened in Las Vegas doesn't happen here in Colorado," said Chris Villalpando, owner of Code 4 Security Services of Fort Collins which provides security for large outdoor events in Denver and along the northern Front Range.
Paddock, a multimillionaire professional gambler with no known ties to terror groups or extremist political organizations, killed 58 people and wounded hundreds in a hail of gunfire that went on for about 10 minutes before he killed himself as police blew the door in on his hotel room.
"There's no way that any good operation would have caught that," Louis Marciani, director of the National Center for Spectator Sports Safety and Security, told The New York Times. "We've now got to go back to the drawing board."
In the wake of the deadliest shooting in modern American history, security professionals will be having conversations about "managing a new set of risks," said Chris Robinette, president of Prevent Advisors, a sports and entertainment security consulting firm. "A lot of us have not gone back to the drawing broad, per se, but we've had to start looking at this a little more broadly, as more like ecosystems as opposed to just the facilities."
Venues in metropolitan areas present unique challenges, he said.
"Those (challenges) are less commonplace than arenas, than stadiums that don't have, as we've seen here in Vegas, potentially line of sight for an active shooter," Robinette said.
Robinette, a Colorado native who was at Fort Carson while in the Army, said Coors Field in Denver is an example of a venue that's vulnerable to similar threats.
"One ... is line of sight from buildings that surround, say, Coors Field," he said. "There's mass transit that comes right up to a number of those facilities - light Rail, and some of those other things - we've seen that that's a susceptible target at times.
"I've been a part of discussions where this has been a hypothetical scenario, so it's not one that has never been thought of. It's just one that has been more unlikely, so there's been less resources dedicated against this particular event or occurrence.
"These things never go unstudied, unaddressed, and we are constantly adapting. As a security professional, I'll tell you, I wake up every morning with the idea of, 'Never again.'"
One of the details of the shooting that stood out to Villalpando was what he referred to as "the fatal funnel." He described the fatal funnel as narrow, confining areas like doorways, stairwells and hallways that offer little to no cover from an active shooter. In the case of the Las Vegas shooting, Villalpando thinks the venue's exit funneled concertgoers trying to escape into a choke point, which was in the line of fire of the shooter.
"We want to consider how we get people out," he said. "Do we have multiple points of exit for people, so they don't go into a fatal funnel while running to get safely away from shooter?"
Preparation for an incident includes coordinating an emergency response, Robinette said.
"If and when these events occur, we now need to be more thoughtful of mass casualty," he said. "How do we evacuate a facility? How do we direct law enforcement into the venue against the threat? How do we direct first responders? Do we have a plan for victims or those injured to move to hospitals on the magnitude that we've seen here? There's a lot of new variables that we now have to take into account."
Security providers in non-metropolitan areas also are reassessing threats. Telluride Town Park hosts iconic events like the Telluride Bluegrass Festival and is not exempt from security concerns.
"We don't have any high-rise buildings like metro areas, but we're in a box canyon," said James Kolar, Telluride's chief marshal. "If someone got up in trees or hillside, it might be just as difficult to spot somebody as it would be from a high-rise building."
The setup of the Las Vegas festival "isn't a great correlation to a venue like Red Rocks," spokesman Brian Kitts wrote in an email, "but we're all feeling the same thing."
The entertainment industry as a whole is devastated, he said. "It's an attack on our fans, our livelihood and the joy we get in putting on shows for our neighbors, family and friends."
"Rather than people feeling nervous, we'd prefer that they be aware. Aware of their physical surroundings and aware of the people around them," he wrote. "We all have to look out for each other. Music, sports and entertainment are an important part of our social lives. Giving in to fear isn't what any of us wants to do."
Red Rocks Amphitheatre staff are doing as much as they can to ensure concertgoers are safe, he said. "We believe our safety protocols are in line with what can realistically be done at any venue - electronic wanding, searches, undercover and uniformed security."
Colorado Springs hosts over 500 special events every year, said Joel Kern, the Police Department's special events sergeant. Many are outside, including the Colorado Classic bike race, the Labor Day Lift Off and Fourth of July celebrations.
Although the Las Vegas shooting will not change police protocol, it is a reminder to officers of the importance of active-shooter preparedness, Kern said.
"I wouldn't discourage people from going to events. That's part of living life and the advantage of living in a city with a lot of special events." Kern said. "You can't operate a state of hyper-paranoia."
He added: "At the end of the day, there's not a 100 percent guarantee on anything."