Red Flag Warning

Locations Affected

Aurora, CO ∙ Denver, CO ∙ Fort Collins, CO ∙ Lakewood, CO ∙ Thornton, CO ∙ Centennial, CO ∙ Westminster, CO ∙ Boulder, CO ∙ Arvada, CO ∙ Greeley, CO

Full Alert Message

URGENT - FIRE WEATHER MESSAGE National Weather Service Denver/Boulder CO 518 AM MDT Tue Apr 21 2026 ...RED FLAG WARNING REMAINS IN EFFECT FROM 10 AM WEDNESDAY TO MIDNIGHT MDT WEDNESDAY NIGHT FOR WIND AND LOW RELATIVE HUMIDITY FOR THE FRONT RANGE FOOTHILLS, URBAN CORRIDOR, PLAINS, AND SOUTH PARK... * AFFECTED AREA...Fire Weather Zones 214, 215, 216, 238, 239, 240, 241, 242, 243, 244, 245, 246, 247, 248, 249, 250 and 251. * TIMING...From 10 AM Wednesday to midnight MDT Wednesday night. * WINDS...Southwest 20 to 30 mph with gusts up to 45 mph. * RELATIVE HUMIDITY...As low as 6 percent. * IMPACTS...Conditions will be favorable for rapid fire spread. Avoid outdoor burning and any activity that may produce a spark and start a wildfire. PRECAUTIONARY/PREPAREDNESS ACTIONS... A Red Flag Warning means that critical fire weather conditions are either occurring now....or will shortly. A combination of strong winds...low relative humidity...and warm temperatures can contribute to extreme fire behavior.

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