BLM Details Why 83,000 Lighting Strikes Started Almost 200 Forest Fires This Summer

 

What triggered the wildfire surge across Interior Alaska around solstice?  

BY BLM ALASKA FIRE SERVICE on AUGUST 29, 2025

More than 170 new wildfires and almost 83,000 lightning strikes in just two weeks.

Between June 15 and June 29, Alaska experienced a significant increase in wildfire activity that closely aligned with a period of intense lightning storms. During this two-week span, 176 new wildfires were reported – 162 lightning-caused, 13 human-caused and one undetermined – resulting in an estimated 344,348 increase in number of acres burned. Several immediately threatened homes, caused major highway delays, and forced evacuations in communities hundreds of miles apart.

This figure does not include holdover fires that emerged later – fires sparked by lightning that smoldered underground for days before flaring up under warmer, drier, and windier conditions.

Map of Alaska showing the varying degrees of concentrated lightning strikes over a two week-period (June 15-30, 2025). There were almost 83,000 ground lightning strikes recorded with the highest concentration appearing in the Fortymile Country near the Canadian Border. Click on this link for a PDF version of this BLM AFS map.

The most active days for fire starts were June 19 and 20, which together accounted for 73 new fires – nearly all lightning-caused. This spike aligned with a period of elevated lightning activity, with almost 83,000 ground strikes recorded statewide. 

The highest daily strike counts were:

• June 17 – 15,718 strikes
• June 19 – 10,716 strikes
• June 20 – 9,943 strikes

This map shows 15,718 recorded ground lightning-strikes across Alaska on June 17, 2025. The key shows how the numbers are divided into BLM Alaska Fire Service and Alaska Division of Forestry zones and areas. The DOF Southwest Area recorded the most lightning strikes with 5,580. Click on this link for a PDF version of this BLM AFS map.

Leading up to the surge, conditions in Interior Alaska – especially near Healy, Fairbanks, and Tok – were primed for wildfire activity. Despite a cool start to June, low humidity began drying surface fuels and duff layers. A sudden shift brought hot, dry weather under a persistent upper-level ridge, pushing temperatures into the 70s and 80s from the Kobuk Valley in northwest Alaska to the Canadian border. Along its southern edge, the ridge triggered thunderstorms that produced dry lightning without significant rainfall.

Spruce Adjective Rating across Alaska on July 15, 2025: Combines thresholds from different fire weather indices. It can best describe the risk for spruce forests, which is Alaska’s main fuel concern starting around summer solstice. Red = EXTREME. Click on this link for this MesoWest Alaska Fuels & Fire application.

This combination of dry fuels, widespread lightning, and simultaneous ignitions led to a rapid escalation in fire activity across a large swath of Alaska, stretching firefighting resources and prompting evacuations, traffic delays, and structure protection across multiple communities for many weeks. In July, the response was stretched across 600 miles as firefighters were simultaneously assigned to protect communities from wildfires in northwest Alaska near Kotzebue to Tok – highlighting the extraordinary scale and complexity of the response effort.

A single-engine water scooper drops water on the Shiliak Fire about 25 miles northeast of Kotzebue in northwestern Alaska on July 3, 2025. Photo by Bill Cramer, BLM AFS

This pattern is not unusual for Alaska around the summer solstice, when nearly 22 hours of daylight allow for maximum surface heating. Similar conditions led to a major lightning outbreak in 2015, highlighting how quickly fire activity can escalate during this time of year. That year, more than 61,000 lightning strikes were recorded during a week surrounding solstice with June 23 at the top with almost 15,000 strikes, resulting in 295 new fire starts in seven days.

Several large fires emerged during this period this year, including:

• Bear Creek and Saint George Creek fires discovered on June 19 near Healy; Nenana Ridge Complex (June 19-20) southwest of Fairbanks; Himalaya Road (June 19) and Aggie Creek(June 20) fires north of Fairbanks; Twelvemile Lake (June 19) and Sand Lake (June 21) fires south of Delta Junction; and 7 Mile Lookout Fire (June 19) near Tok. All were managed by the Alaska Division of Forestry & Fire Protection.
• The Ptarmigan Complex of eight fires discovered June 19-20 near Central and the Ninetyeight Fire discovered on June 19. Both were managed by the BLM Alaska Fire Service.
• Roundabout Complex of six fires discovered between June 15-20 near the remote Koyukuk River village of Huslia, managed by the BLM AFS. While the fires in this complex prompted an initial response and staffing in June, most of its fire growth occurred in July.
• Lush Fire discovered near Rampart on June 18 and managed by BLM AFS.

Photos of fires burning in Alaska around solstice include: (starting from the far upper left going clockwise) the Bear Creek Fire near Healy; the Twelvemile Lake Fire near Delta Junction on June 20; the Ninetyeight Fire burning north of the Salcha River on June 19 (lower right photo); the Bonanza Creek Fire southwest of Fairbanks on June 20; a bulldozer with the Himalaya Fire burning in the background north of Fairbanks on June 21; the 7 Mile Lookout Fire near Tok on June 21; and the Lush Fire as seen from the Rampart airstrip on June 21. BLM AFS and DOF photos

As of Aug. 29, the 2025 wildfire season is winding down, with 448 fires burning just over 1 million acres statewide. Of those, 250 fires – about 57% – were considered naturally caused, with nearly all attributed to lightning. By comparison, the 2015 season saw 768 fires burn approximately 5.1 million acres, making it the second-largest fire season on record since tracking began in 1939. That year, 54% of the fires were attributed to lightning. While fire tracking began in 1939, more consistent and reliable acreage records date back to 1950. Since then, six of the top 10 fire seasons by acres burned since reliable record-keeping began in 1950 have occurred within the past 20 years. The record remains 6.5 million acres burned in 2004, with 2005 ranking fifth at 4.6 million acres. This year currently ranks 22^nd.

Fire history from 2000 until Aug. 29, 2025. Find a PDF version of this map here. 

These years serve as powerful reminders of the variability and potential severity of Alaska’s wildfire seasons, and the toll they can take on communities across the state. The widespread effects this year highlight the success of coordinated response efforts – spanning vast distances and involving multiple agencies and jurisdictions. They also underscore the importance of public preparedness in building wildfire resilience.

This article was compiled with support from the Alaska Interagency Coordination Center (AICC) Predictive Services and BLM Alaska Fire Service Geographic Information Systems Specialists. It incorporates wildfire statistics and geospatial data from the AICC Lightning Database, AICC Situation Report Exports and archived fire history records available on the AICC website. It also includes fire weather and fuel condition data from the MesoWest Alaska Fire & Fuels site, which is linked through the AICC Predictive Services Fire Weather page.

For more information, contact BLM Alaska Fire Service Public Affairs Specialist Beth Ipsen at eipsen@blm.gov or (907)356-5510.

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