20 million Americans in 8 states under red flag fire danger warnings

(NEW YORK) — More than 20 million Americans in eight states were under red flag warnings Tuesday morning as severe winds and dry conditions have elevated the threat of fire danger.

The alarming forecast comes in the wake of a deadly tornado outbreak over the weekend in the Midwest and South, and wind-whipped wildfires that destroyed hundreds of homes in Oklahoma.

The National Weather Service on Tuesday issued red flag warnings for a large portion of Oklahoma — including Oklahoma City, Stillwater and Wichita Falls. The NWS office in Norman, Oklahoma, said possible wind gusts of up to 45 mph combined with low relative humidity and dry conditions are producing “critical to extreme” fire danger in Oklahoma and North Texas.

Extremely critical fire danger is also forecast Tuesday for the entire state of Kansas, parts of Arizona, a major portion of Missouri, eastern Colorado and West Texas, including the Texas Panhandle.

Other major cities under red flag warnings on Tuesday are Denver; Albuquerque, New Mexico; Kansas City and Springfield, Missouri; and the Texas cities of Austin, San Antonio and El Paso.

The areas under red flag warnings are being warned that the conditions are rife for fires to spread rapidly, which makes them extremely hard to contain.

Relative humidity across the alert areas is 15% to as low as 6%, and wind gusts are forecast to be between 40 and 75 mph.

The critical fire danger comes just as people are beginning to recover from devastating wildfires in Oklahoma and a series of tornadoes.

At least 42 people were killed amid more than 970 severe storm reports — including tornadoes, severe storms, dust storms and fires — across more than two dozen states over the weekend. A three-day tornado outbreak tore through at least nine states.

Raging wildfires in Oklahoma over the weekend left four people dead and more than 140 others injured, according to the state’s medical examiner.

The Oklahoma wildfires destroyed more than 400 homes and structures and burned at least 170,000 acres, prompting evacuations amid extreme fire weather conditions.

Wildfires also raged in Texas over the weekend. The biggest blaze was the Windmill Fire that ignited in Roberts County and quickly spread to 21,000 acres, the Texas A&M Forest Service said. The fire was 95% contained on Monday.

Parts of Gray County were temporarily under a mandatory evacuation due to the Rest Area Fire, the Texas A&M Forest Service said. The fire has burned an estimated 3,000 acres and was 30% contained as of Friday evening, according to the forest service.

ABC News’ Kenton Gewecke contributed to this report.