INFO

Slos stands for Several Laps of Sanitas. It is a 50K ultramarathon unfolding in Boulder, Colorado. This race challenges runners to circumnavigate Mount Sanitas five times, totaling 33.8 miles with 6,895 feet of elevation gain. Born from a joke among friends, Slos has grown into a spirited event that combines physical endurance with a sense of community and humor.

The race starts and finishes in the backyard of its creator, Michael Bateman, which also serves as the aid station. Here, participants can refuel with food and drinks between laps, ensuring they’re ready to tackle the next loop. You MUST touch the fence after every lap in order to be qulaified. A recommended donation of $25 is appreciated to help cover the cost of refreshments. For those who aren’t running but want to be part of the fun, volunteers are welcome! If you’re interested in lending a hand, email Michael at michaelbateman@gmail.com to get involved. Slos promises an unforgettable day of camaraderie, grit, and grassroots racing in Boulder’s backyard.

DATE/TIME
May 4th, 2025 - 7:00 am

ADDRESS
2530 9th St, Boulder, CO 80304

CONTACT
Phone: 336-698-5053
Email: taylorrosewoolley@gmail.com