The National Weather Service (NWS) in Billings, Montana, has issued multiple Red Flag Warnings active for parts of Montana, Wyoming, and South Dakota. One warning, issued on October 23 at 1:30 PM MDT, is set to remain in effect until October 24 at 12:00 AM MDT. Another warning, issued on October 22 at 12:14 PM MDT, was in effect until 9:00 PM MDT on October 23. These warnings highlight conditions conducive to extreme fire behavior across specific regions.

The affected areas include the Northern Cheyenne Indian Reservation, Ashland Ranger District of Custer National Forest, Sioux Ranger District of Custer National Forest, and areas under Sheridan County/Casper BLM. The warnings encompass North Central Wyoming Fire Zone 274, Southeast Montana Fire Zone 131, and Southeast Montana and Northwest South Dakota Fire Zone 133. Counties affected are Sheridan in North Central Wyoming; Harding in Northwest South Dakota; and Big Horn, Carter, Fallon, Powder River, Rosebud, and Treasure in Southeast Montana. Forecasters anticipate the most dangerous conditions along and southeast of a line extending from Baker, Montana, to Sheridan, Wyoming.

Conditions expected include low humidities, unseasonably warm temperatures, and strong, gusty winds. These factors are predicted to create erratic fire behavior, making new or existing fires difficult to control. Southwest winds are expected to blow at 20 to 30 mph, with gusts reaching up to 45 mph. A cold front is anticipated to arrive from late afternoon into early evening, causing winds to shift to the northwest. Gusts up to 45 mph are expected to continue through much of Friday night.

Humidity levels are forecast to drop to between 14 and 25 percent. Temperatures are expected to reach highs of 75 to 85 degrees Fahrenheit. This combination of dry air, warm temperatures, and strong winds increases the risk of wildfires starting easily and spreading rapidly. Such conditions can lead to rapid wildfire spread.