Billy Howarth filled a plastic bottle with bright blue cornstarch and patiently waited for the first of the Color Run participants to pass through the blue zone.
"They told us we have to go like a hose," said Howarth, a 21-year-old University of Delaware student in town to volunteer as a color thrower for Saturday's 5K run, as he motioned the bottle from side to side. "You can't go up and down. And for little kids we have to do it gently."
The color throwers covered their mouths with bandannas as the first runners came through, pelting them with blue until a cloud of color rose high into the air in the parking lot near Oriole Park at Camden Yards. Blue was the last of five colors the runners would race through before crossing the finish line.
Saturday marked Baltimore's third Color Run, an event that bills itself as "the happiest 5K on the planet" and leaves runners who show up in white T-shirts and rainbow headbands covered in a kaleidoscope of yellow, green, orange, blue and purple. And in case participants were not colorful enough after finishing a course that wound around the lots of Camden Yards and M&T Bank Stadium, the event ended with an emcee on a stage who encouraged runners to dance and throw extra packages of color into the air at once.
"I've only lived in Baltimore for a year, so it's a good way to open myself up to my new city," said Dede Fago, 25, who ran with her boyfriend, Matthew Knoerlein, 27. "At the color [stations] everyone is dancing but you can't really see anything, and it's a cloud of color everywhere. It's my favorite race."
"It's what got me into running," added Knoerlein.
About 10,000 people signed up for the morning race and about 7,000 registered for the afternoon race, according to race director Amanda Blanck. The event, which drew an estimated 25,000 when first held in Baltimore last spring, has spread to hundreds of cities around the world since it began in 2012.
"It's a fun atmosphere, you don't have to worry about elite runners running over you," said Sherry Ross, 48, of Harpers Ferry, W.Va., as she and two friends prepared for the race. Their purple, black and white tutus were leftover from the Polar Bear Plunge, she said.
Many participants added tutus, wigs and animal ears, or other accessories to their running wardrobe, including 36-year-old Landon Baker, who wore a pink mohawk wig, a pink mustache, pink glasses and a tutu. He said his outfit was inspired by "wildness."
Sharee Harris, who sported a curly rainbow wig she picked up at Party City, said she had been trying to get in shape and the race had been a goal since last year.
"This is my first 5K and I thought it would be really motivating," said Harris, of Glen Burnie. "The goal last year was to get on the rides at Disney, now I'm just trying to get sexy for my 35th [birthday] in December."
The event drew participants of all ages. Brigitte Frasier of Upperco came with her three sons and one of her son's girlfriends.
"It was very joyful, I would say, everybody was laughing and having a good time," Frasier, 49, said after the race. The colors "kind of took our breath away at first ... you learn to hold your breath as you go through."