Hundreds of thousands of notoriously loud Seahawks fans are cranking up the noise, as they cheer, chant and go berserk during a parade to celebrate the franchise's first Super Bowl victory.

The mood in downtown Seattle was electrifying, as the parade featuring the Super Bowl champions got underway Wednesday near the Space Needle.

Revelers packed the 2-mile route. They wore blue and green wigs, waved flags, scarves and signs, and erupted into spontaneous song and dance.

The Washington National Guard is escorting many of the players in Humvees and other military vehicles under blue skies and freezing temperatures. Others are riding in Ride the Duck amphibious vehicles used to take tourists around the city.

Police estimated about 700,000 people are attending the event — that's more than the city's population — in perhaps the largest gathering in Seattle history.

The parade is heading to CenturyLink Field, where a ceremony will mark the team's first Lombardi Trophy in 38 seasons.

The cheers are likely to get more boisterous as fans observe a "moment of loudness" at 12:12 p.m.

Dakota Heaphy, 20, who called himself a lifelong Seahawks fan, drove all night from Cheyenne, Wyo., — more than 1,400 miles and 18 1/2 hours. Heaphy, who works as a forklift operator, said his boss, a Denver Broncos fan, gave him and another co-worker time off to celebrate.

Shawn Cooper and Marlana Studebaker of Covington staked out a spot near the route start hours before the event started. They had supersized photo cutouts of quarterback Russell Wilson and cornerback Richard Sherman, prompting many to stop and take photos.

"This was a long-awaited win. It's well worth the wait," Cooper said. "They're years ahead of their time which makes me believe there's another one coming."

Many fans had camped out overnight to reserve front-row seats along the route, braving freezing temperatures.

Others perched on window sills and balconies, climbed atop trees and pillars, or sat on sturdier shoulders to get a better view.

At Westlake Plaza in the middle of the route, fans wore blue and green wigs and team-colored tutus, thronged shoulder to shoulder and sang as they waited.

They chanted "Seahawks, Seahawks," as a Pearl Jam song blared from the shopping center's speakers.

Chris Hoops, a sales worker from Everett, leaned against a pillar with two of his school-aged daughters looking awfully cold as they bundled in sleeping bags at his feet.

The family left home at 7 a.m. to get a good spot for the parade. The girls, 11-year-old Emily and 8-year-old Bella, warmed up when they were asked whether they were sorry about missing school. They shouted "No" in unison.

Bubba Lezard, 28, from Enumclaw, said his tribe, the Muckleshoot Indian Tribe, gave everyone the day off in honor of the Super Bowl champions. He, his wife and 6-month old baby drove 1.5 hours into Seattle for what he called a "once in a lifetime" experience.

Boeing's 747-8 airplane painted in Seahawks colors is expected to fly over the stadium during the celebration at CenturyLink Field.