In a typical year, the Grandma’s Marathon weekend along Minnesota’s North Shore attracts about 20,000 participants. The featured event each June is the 26.2-mile race between Two Harbors and Duluth. In 2020, all in-person races were canceled due to COVID-19.
For 2021, Grandma’s plans to thin the pack to half its normal capacity for a safer pandemic race environment. Organizers have also hired a leading name in the field of crowd science to help create an optimal flow.
So, what exactly is crowd science?
Pre-COVID, Marcel Altenburg of Manchester Metropolitan University was already a consultant for marathons worldwide, including in New York, London, and Chicago. (Additionally, pro sports stadiums, airports, and even the New York Times assessing the size of President Trump’s inauguration crowd have employed his expertise.)
Altenburg developed the Start Right software featuring an algorithm that takes every dimension of the race into account. It measures participant density and spacing from the starting line, through the aid stations and narrow road sections, and past the finish lines. With it, marathon organizers can predict and manage a race’s flow to prevent bottlenecks and other safety hazards. Add the challenges of the pandemic and that’s yet another calculation for thousands of bodies traveling at top speed.
“Grandma’s Marathon is unique in its setup and all measurements of the event are very fortunate,” Altenburg said in a release. “With the right adjustments, this race can be organized with social distance in the place at the start, through the course, and at the finish.”
Here’s a video showing Altenburg’s calculations in action:
Along with fewer racers, Grandma’s Marathon has made adjustments to bus capacity (25 people maximum) to the start line. Once there, racers will be spaced out and have groups of five released in a staggered fashion. All people on site must wear masks or face coverings—except for participants during the race itself.
With this plan, Altenburg estimates racers should have at least 12 feet, and often up to 20 feet, between each other. At the finish line, the plan decreases peak crowd density by 64% from the 2019 marathon.
“With this analysis, we know our racecourse and the established capacity limits allow for the appropriate spacing between participants,” Grandma’s Marathon race director Greg Haapala said in the release. “But we will still require everyone involved to act responsibly throughout the event.”
Grandma’s Marathon is June 19, 2021. The in-person event is at capacity. Learn more about virtual options and check race status at the marathon’s website.