Jessi Fehrenbach and Seana O'Neill were at the opposite end of Town Branch Trail from their car when the big black cloud appeared on the horizon.
They whipped out an iPhone to check on the weather, but it was too late.
"We saw the storm on the radar and thought we better get going, then 'We're in it now,'" Fehrenbach said as she and O'Neill, both completely soaked, loaded their bikes on their vehicle.
They didn't seem to mind, explaining that they live downtown and like to bike, and are looking forward to the day when the trail reaches them.
Sunday was the trail's first Trailapalooza celebration.
The rain was intense for 20 minutes, but the cliché about it not dampening spirits applies here.
Big Maracas, the band that was playing when the storm hit, kept right on playing.
Some people found a tent to get under. Others just kept walking, skating or walking in the rain.
Van Meter Pettit, the president of the trail board, said the purpose of the day wasn't to celebrate new pavement (the trail, which starts across Lees town Road from Masterson Station Park, is 1.8 miles long and eventually will be 8 miles).
"Half the job is building the trail and the other half is bringing awareness so people will use the trail," he said.
Sunday's event featured a scavenger hunt, free food and water, information about healthier living, Presto! The People Powered Piano Bike, the March Madness Marching Band, and Big Maracas.
There was a short period of "speechifying" that included turns at the bullhorn by several Urban County Council members, Mayor Jim Newberry and Vice Mayor Jim Gray.
Newberry talked about the popularity of trails.
"It seems like every time we put down some asphalt on a trail, about the time it cools off there are people all over it," he said.
Gray talked about the history one could learn from walking the Town Branch Trail.
"This project represents a beacon of light ... because it connects our past with our future," he said.