WGBT threshold for Twin Cities race cancellation

The black curved line (curve of best fit) represents the number of runners who dropped out of the race plus the number seen in the finish line medical tent per 1000 race finishers. The red line intersecting the curve of best fit is placed just above the data points associated with an MCI—three hospitals forced onto ambulance diversion—and below the data points associated with a major MCI—six hospitals forced onto ambulance diversion and activation of regional EMS transport teams. The numbers in white boxes are the approximate number of runners who developed EHS per 10,000 finishers for a given WGBT range. Zones of relative risk for EHS by WBGT are designated by color: Green (low risk) is <13°C or 55°F; yellow (moderate risk) is 13.5 to 18°C, or 56 to 64°F; red (high risk) is 18.5 to 20°C, or 65 to 68°F; and black, which is not drawn (very high risk; cancel race), is ≥20.5°C or 69°F.