Georgia Tech is well-known for their HIGH-tech. Now they’ve come through again. See their risk-assessment tool at https://covid19risk.biosci.gatech.edu/. The risk level is the estimated chance (0-100%) that at least 1 COVID-19 positive individual will be present at an event in a county, given the size of the event. Just use the drop-down to pick the county then use the slider to set the event size. (Thanks Caleb!)