A crowd of thousands turned Seattle into a blizzard of snow balls on Saturday as the US city's downtown area played host to area a record-breaking icy battle.

In the shadow of the iconic Space Needle landmark, 5,834 people helped set a new world record for the largest snowball fight.

More than 30 truckloads of snow were brought in from the nearby neighbourhood of Cascades for the event, which included a snow fort building competition and pub crawl.

The epic battle helped mark Snow Day, a fundraiser for local children's charity The Boys and Girls Clubs of King County.

Each participant threw at least one snowball during the attempt, which beat the previous world record of 5,387 at a 2010 snowball fight in South Korea.