The National Weather Service had 169 active Red Flag Warnings posted Thursday across 21 states and the District of Columbia, more than double the 79 warnings in 16 states a day earlier — which had themselves more than doubled from 36 warnings the day before that. Eight states joined the list for the first time this week: Arizona, Idaho, Massachusetts, Maine, Oregon, Pennsylvania, Vermont and West Virginia. Indiana and Wyoming, both on Wednesday’s list, dropped off Thursday’s.
The bulk of Thursday’s warnings remain concentrated around the Great Lakes, where wildfire smoke has now created a hazard beyond fire danger on land. The Weather Service posted a run of marine warnings across Lakes Michigan, Erie and Huron for dense smoke reducing visibility to less than one nautical mile, making navigation difficult for vessels on the open water. The New Buffalo, Michigan, to St. Joseph, Michigan, and Michigan City, Indiana, to New Buffalo zones were covered until 2 p.m. EDT Thursday afternoon. Additional marine zones affected span Lake Erie from Ripley to Buffalo, New York, and Maumee Bay to the Islands, Ohio, along with a chain of warnings covering Green Bay, Wisconsin, and Lake Michigan’s shoreline from Sturgeon Bay to Two Rivers, Wisconsin, and Sheboygan to Port Washington, Wisconsin.
On land, the push into the Mid-Atlantic and New England — Pennsylvania, Vermont, Massachusetts, Maine and West Virginia appearing for the first time this week — shows fire weather risk extending east from its earlier Great Lakes and Pacific Northwest footprint. Arizona and Idaho’s addition points to fire danger returning to the interior West even as Wyoming cleared Thursday’s list.
The day-to-day churn in the warning map — new states added, others removed, the total nearly doubling in 24 hours — reflects how fast Red Flag conditions can shift with changes in humidity, wind and vegetation dryness. The National Weather Service continues to update warnings by region as conditions evolve; residents in newly listed areas, including around Chicago weather and Detroit weather, should avoid outdoor burning and stay alert for rapidly changing fire behavior through the posted warning periods, which vary by zone.
With alerts now reaching both coasts and the interior West, Thursday’s total of 169 is the highest of the week, and the National Weather Service has given no indication the pattern has peaked.