The National Weather Service had 36 active Red Flag Warnings posted Tuesday across 11 states, nearly triple the 13 alerts in place a day earlier, as fire weather risk spread far beyond its recent foothold in the northern Plains.
Tuesday’s warnings cover California, Colorado, Illinois, Massachusetts, Minnesota, New Jersey, New York, Ohio, Pennsylvania, South Dakota and Wyoming, according to the National Weather Service. That is more than double the five states under warnings a day earlier and marks a sharp reversal from the contraction reported Monday, when Idaho, Montana and Oregon had dropped off the map.
The new alerts bring a different kind of threat to Trinity, Humboldt and Siskiyou counties in Northern California, where the National Weather Service warned of isolated to scattered dry thunderstorms Tuesday afternoon and evening capable of producing outflow winds gusting to 50 mph or higher, with activity potentially continuing overnight into Wednesday. Dry lightning paired with erratic winds raises the risk of new fire starts in terrain already carrying elevated fire danger.
The northern Plains, the epicenter of the past several days’ fire weather, remains under warning until 9 p.m. MDT Tuesday. South Dakota’s warning spans Fall River County, the Northern and Eastern Foot Hills, Custer County Plains, Pine Ridge, Butte County, Perkins County, Ziebach County, Haakon County, the Badlands, and Northern and Southern Campbell County, driven by gusty winds and low relative humidity. Wyoming’s Crook County Plains and Weston County Plains carry the same warning.
Fire weather has also pushed into the Great Lakes and industrial Midwest, with warnings posted in Minnesota’s Koochiching, North St. Louis and northern Cook/Lake counties, and across a broad swath of Ohio counties including Franklin, Licking, Fairfield, Butler, Warren and Hamilton. In the Northeast, warnings now extend across southeastern Massachusetts — Bristol, Plymouth, Barnstable, Dukes and Nantucket counties — a region untouched by Monday’s alerts.
The National Weather Service says a Red Flag Warning means critical fire weather conditions are either occurring or expected shortly, with the combination of strong winds, low humidity and warm temperatures capable of driving rapid fire growth. The agency is urging residents in warned areas to avoid outdoor burning and report smoke or fire starts immediately.
With warnings now covering more than double Monday’s geographic footprint, forecasters will be watching whether the expansion into the Midwest and Northeast proves temporary, tied to a passing weather system, or whether the broader footprint holds into midweek.