WASHINGTON -- Sometime during D.C. United’s encounter with the New York Red Bulls this past Sunday at RFK Stadium, the ground beneath me began to shake.

It’s a feeling to which many fans at the venue have grown accustomed. Among the stadium’s signature features are some unusually flexible bleachers at the northeast side of the field, movable banks of seating that bounce wildly under the weight of airborne supporters.

However, I was not on the northeast sideline. I was in the press box on the opposite side of the field, and above me in the upper deck, quite a ways to my left, were about 600 quite excited New York Red Bulls fans. I felt compelled to record the tremor on my cell phone.

If you don't believe me about those #RBNY away fans shaking the press box at RFK with their chanting/jumping....#DCU pic.twitter.com/TQP9pKFvrX — Pablo Maurer (@MLSist) November 1, 2015

This was not, however, the most memorable fan-related moment I’d seen in this rivalry. Not by a long shot. Three years ago, in the upper deck at Red Bull Arena, I caught some far less uneasy feelings.

It seems like almost a yearly tradition at this point: D.C. United and the Red Bulls, MLS originals with an ever-intensifying hatred for one another, meet in the playoffs.

And right around this time every year, you’ll see the same sort of articles crop up around the web—lists of unforgettable moments in the rivalry, flashbacks to notable incidents. Alecko Eskandarian spewing Red Bull all over the pitch at Giants Stadium. Cheatin’ Bob. That unforgettable image of Thierry Henry laughing maniacally after shattering D.C.’s dreams in 2014.

But nothing—and I mean nothing—will compare to what happened in D.C. and New York’s Conference Semifinal matchup in 2012.

We all know the on-the-field story by now. United fans, surely, still watch the video of Bill Hamid’s meltdown, Joe Willis’ penalty kick heroics and Nick DeLeon’s late game-winner on a monthly basis. Red Bulls fans probably struggled to block it from their memory until their triumph in 2014.

It was what happened the night before, though, that sticks with me. Hurricane Sandy had already forced the two teams to swap home dates, and as the return leg of the series approached, a freak snowstorm was bearing down on the New York metro area. Hours before game time, I arrived at Red Bull Arena to find it completely covered in snow.

Jimi Butler, who puts together the road trips for the D.C. United supporters' group Screaming Eagles (and will do so again on Sunday), took a moment this week to share his recollection of the events that followed. He was among 350 or so United fans that trekked to Red Bull Arena on a weeknight for the match, missing work and knowing full well they might not even get to see the game played at all.

Photo by Pablo Maurer / @MLSist

“Our biggest fear was that the match was going to be canceled, but we were continuously assured that, 'It’s definitely going on, it’s definitely going on,'” Butler says. "We got into the stadium and looked down onto the field and thought, ‘Oh my God, this is not happening.’”

I had come to the game to shoot photos, and everyone, including the Commissioner himself, was shoveling snow. It seemed an exercise in futility. United’s players and coaches were growing impatient; it was clear they’d come to play. I asked D.C. head coach Ben Olsen what he thought of the snow as he was walking off the pitch earlier in the evening. He grinned widely, then said, quite simply, “It’s perfect. This is perfect.”

Photo by Pablo Maurer / @MLSist

New York, on the other hand, wanted none of it. Outside of the home locker room, you could hear Red Bulls head coach Hans Backe lobbying to have the match postponed. Henry was doing plenty of his trademark gesticulating–not at his teammates, for once. His frustration was directed at those deciding whether to hold the match at all.

“You start to hear the grumblings in our section," Butler recalls. "'Is the match going to happen? Why did they tell us we were playing if we weren’t going to play?’ You could begin to sense that things might start taking a turn for the worse.

“Right around that time, when we were starting to get that feeling, [the leaders of the other supporters’ groups] and myself got pulled aside by [former DC United President] Kevin Payne and [Executive Vice President] Stephen Zack to go talk to them. They told us, 'There’s a possibility that the game might not happen and we may have to reschedule it. What do you think is going to happen if we tell everybody that this game isn’t happening?'”

Butler and company didn’t really know what to say. “I told them, ‘I don’t know, we can’t control all these people.’ I mean I don’t think they would’ve caused any harm or anything but you definitely have people who were very angry and upset," he says. “Within a minute or two of that meeting, we see the Red Bull players basically bolting off the pitch. We said, 'Oh boy, they just canceled it.’"

By this time, I’d worked my way onto the field, hoping to salvage what I could of my night, photo-wise. I ended up following D.C. winger Chris Pontius and former United defender Brandon McDonald towards United’s away support.

“All of the sudden, we started to see our players coming over,” said Butler. “It was almost like a vacuum that sucked the negativity that had begun to brew away. We were watching the Red Bulls players just take off, just run off the pitch [without thanking their fans]. When our players came over, the whole mood in our section completely changed. People started cheering, singing, yelling, the flags got going.”

Pontius and company were not done. As he and McDonald approached the ad boards, he turned to his teammate and suggested they get even closer to the fans.

I could barely keep up as D.C’s players–skidding perilously as their cleats clanked up several flights of ice-covered metal steps–charged towards the upper deck. Payne looked genuinely gobsmacked to see his men breeze by him on their way out to greet the fans. It was, plain and simple, a purely spontaneous act.

“The Red Bulls, they took off,” said Butler. “Their fans were left out in the snow, the cold. Our players came all the way up to [the upper deck to] thank us. They’re taking selfies with everyone; everyone is singing, dancing, beating the drums--even [D.C. United co-owner] Will Chang is up there playing the drum. I don’t think you’d ever see that anywhere else."

Photo by Pablo Maurer / @MLSist

“Those are the types of things that endear our fans to our players, because they do things like that," Butler says. "I don’t even think you could’ve possibly rehearsed that. It was just one after the other, going up there.”

The good faith shown by D.C.’s players that night brought many fans back the following evening. At least 300 or so were in attendance when DeLeon put United through to the Eastern Conference Championship. When he scored his game-winner, he charged right towards them, pounding his chest and pointing to the badge on this jersey.

“I know all the people that were at that match,” Butler says, starting to chuckle. “I have all the records of the emails, I know who was on what bus. I can tell you this--even though that was only three years ago, I think the number of people claiming that they were at that match has quadrupled.”