The musicians performed along with Big Head Todd & the Monsters and members of the Lumineers, among others at the United Ways of Colorado Flood Recovery Fund event.
Matthews told the crowd, "I'm very honoured to be with you all, making the noise. When we all get together, we can make a noise. To let people know there is more work to do!"
And The Fray drummer Ben Wysocki added, "We are proud to be Coloradans. Living here and having so much family up north in Boulder and all that, this was something that was a reality you know not for any of our homes or our situations, but friends and family... This was our neighbourhood."
The Colorado floods hit in September (13) and resulted in nine deaths and billions of dollars in damage.