(NEXSTAR) — You may have seen a weather alert in your area or elsewhere that you didn’t recognize recently, especially leading into the summer months. Do you know what a “red flag warning” means?

RFWs are issued when there’s a heightened chance of fires in an area.

While different regions define RFWs differently, the National Weather Service outlines some basics:

  • warm temperatures
  • very low humidities
  • stronger winds are expected to combine, producing an increased risk of fire danger

“On a windy but humid day, you won’t have a red flag warning,” says David Yeomans, chief meteorologist at KXAN News in Austin. “Or even if it’s windy with low humidity (below 20%), if you’ve had a ton of rain recently, you won’t have an RFW either.”

Yeomans adds that gusty winds over 25-30 miles per hour can aid in spreading fire, triggering a RFW.

The National Integrated Drought Information System, which monitors and plans for droughts in the U.S., says there’s some contention over RFWs among both the NWS and fire officials, saying some worry it’s “not an effective messaging medium.” Several agencies collaborated in 2018 to research and assess what might work better — but changing the system has proven difficult.

“Changing the RFW product has challenges not seen in most other NWS hazard messaging because it needs to include aspects of both weather and vegetation conditions, and may or may not include the presence of wildfire,” NIDIS explains.

Additionally, the organization says because different areas of the country have different parameters for RFWs, it can be hard for even experts to make the call.

NWS has a few recommendations for RFW conditions in general.

  • If burning is allowed in your area, all barrels should be covered with a weighted metal cover. Covers should not have any holes larger than 3/4 of an inch
  • No cigarettes or matches should be thrown from a moving vehicle
  • Outdoor fires should be extinguished properly, including thorough water dousing — even dunking charcoal in water is suggested
  • Never leave fires unattended