The Centers for Disease Control and Prevention, faced with the reality of much of the country's reopening, released guidelines Friday for events and gatherings like weddings, concerts, festivals, parades and conferences.

The agency classified gatherings into four risk categories:

• Lowest risk: Virtual only gatherings
• More risk: Small outdoor, in-person gatherings where everyone is from the same area, stays 6 feet apart, wears face coverings and doesn't pass anything back and forth
• Higher risk: Medium in-person gathering where everyone can stay 6 feet apart
• Highest risk: Large in-person gatherings where it's hard to stay 6 feet apart and people are coming from outside the local area

With those categories in mind, the CDC's extensive guidelines advise event planners to make sure staff is following proper hygiene and disinfecting protocol. Staff are required to wear face coverings and attendees are encouraged to do so, especially "in settings where individuals might raise their voice (e.g., shouting, chanting, singing)."

Any large events should "broadcast regular announcements on reducing the spread of COVID-19 on public address systems," the guidelines say.

If the gathering is indoors, there should be as much ventilation as possible to bring in outside air.

Extra care should be paid to make sure people don't line up or overcrowd restrooms.

In general, the more people gather in one place and the longer they're around each other, the higher the risk, says the CDC. An area with higher rates of community transmission also adds another layer of risk.

It's also important to note that the CDC guidelines don't overrule any state or local rules in place.

See the full CDC guidelines here.