Minnesota weather: Air quality alert for wildfire smoke expands to include Twin Cities

(FOX 9) - Smoke from wildfires burning in northern Minnesota and Canada has prompted an expanded air quality alert across much of the state, while dry, hot and windy conditions continue to fuel extreme fire danger in the northeastern part of the state. 

Multiple wildfires continue to burn across northern Minnesota, prompting Gov. Tim Walz to declare a peacetime emergency and mobilize the Minnesota National Guard in response to the blaze. Meanwhile, federal officials have closed the Boundary Waters Canoe Area Wilderness on Tuesday and evacuations are underway. 

Live updates: FOX 9's ongoing coverage of the northern Minnesota wildfires 

Air quality alert expanded as wildfire smoke spreads

Expanded air quality alert:

The Minnesota Pollution Control Agency has expanded its air quality alert to cover much of Minnesota from 9 a.m. Tuesday through 11 a.m. Friday as smoke from wildfires is expected to spread across the state.

The alert expanded from northeastern regions to include east central, central, west central, southeast, north central, and north-west Minnesota. The impacted areas include Twin Cities metro, Brainerd, St. Cloud, Alexandria, Hinckley, Winona, Moorhead, International Falls, Duluth, Two Harbors, Hibbing, Ely and several Tribal Nations.

Officials say very heavy smoke will blanket the Arrowhead on Tuesday before pushing south into central Minnesota Tuesday night and reaching the Twin Cities and southeastern Minnesota by Wednesday. Additional rounds of heavy smoke are possible through Friday morning.

The MPCA expects air quality to reach the maroon Air Quality Index (AQI) category, which is considered hazardous for everyone, in parts of northeast Minnesota. Air quality is forecast to reach the "very unhealthy" category in Hibbing, Ely, Duluth and Hinckley, while the rest of the alert area, including the Twin Cities, is expected to see red, or "unhealthy," air quality.

What you can do:

Residents are urged to avoid prolonged or strenuous outdoor activity, stay indoors as much as possible and consider moving outdoor sports and events inside. The sky may appear hazy and smoky, and the air could have a strong smell of smoke.

Red flag warning and enhanced burning restrictions

Red flag warning Tuesday:

The National Weather Service has issued a red flag warning for Cook, Koochiching, Lake and St. Louis counties from noon to 9 p.m. Tuesday.

Red flag warnings are issued when dry conditions and strong winds occur that can make fires spread and get out of control quickly, according to the DNR. 

"When fire risk is this high, it's important to be careful with anything that could spark a wildfire," said Karen Harrison, the Minnesota DNR wildfire prevention specialist. "People should use extreme caution until conditions improve."

Officials are urging residents not to burn in counties where the warning is in effect and to check any recent burning to ensure fires are completely out. The DNR will not issue or activate open burning permits for large vegetative debris burning and said campfires are discouraged. 

Additionally, officials emphasize using caution with activities that can cause sparks or heat near vegetation, including securing trailer chains, parking ATVs on gravel or pavement or using chainsaws.

Other restrictions:

Enhanced burning restrictions remain in effect in Cook, Lake and northern St. Louis counties. Under the restrictions, campfires are prohibited in backcountry areas, state forests, campgrounds and recreation areas, fireworks are banned outside city limits, and open burning permits will not be issued or activated.

Similar restrictions are also in effect through the Bois Forte Band of Chippewa, Voyageurs National Park and the U.S. Forest Service in the Boundary Waters Canoe Area Wilderness and Superior National Forest.

For the latest fire danger and burning restrictions, visit the Minnesota DNR website. 

Extreme heat warning across Minnesota

Extreme heat:

An extreme heat warning remains in effect for much of Minnesota through Thursday, while a heat advisory continues for far southeastern Minnesota and portions of west-central Minnesota.

Temperatures will hold steady in the 90s for much of the week with heat index values nearing 100 degrees. Overnight lows stay warm and muggy in the upper 60s and low to mid-70s.