Satellite Imagery Suggests the Bear Fire Grew by 250,000 Acres in 24 Hours

As firefighters and rescue officials worked all night to evacuate areas impacted by the wind-fueled Bear Fire (part of the North Complex Fire), satellite heat detection was showing the incredible growth of the fire. On the morning of September 8, the North Complex Fire sat at 58,404 acres. In just 24 hours since, the fire could have grown as large as 300,000 acres, putting it in the top 5 of largest wildfires ever recorded in California history.
UCLA climate scientist Daniel Swain analyzed the the satellite imagery on the morning of September 9 and conservatively estimated the Bear Fire grew 250,000 acres in 24 hours.
To put last night’s incredible southwestward run on #BearFire into perspective: a conservative estimate based on current satellite heat detections suggests fire expanded by ~250,000 acres in ~24 hours. Fire now directly threatening Oroville, Hwy 70 corridor. #CAwx #CAfire pic.twitter.com/4J6epC1FyR
— Daniel Swain (@Weather_West) September 9, 2020
“To put last night’s incredible southwestward run on #BearFire into perspective: a conservative estimate based on current satellite heat detections suggests fire expanded by ~250,000 acres in ~24 hours,” Swain wrote on Twitter.
The fire grew into the areas surrounding Lake Oroville, forcing thousands of nearby residents to flee their homes. Here’s the evacuation map as of Wednesday morning:

PG&E cameras and on-location journalists show a fire spreading at an alarming rate as a historic heat wave and 50 mph winds pushed the fire to extreme growth. Here are some of the incredible views of the fire overnight:
The #BearFire photographed from a dock on Lake Oroville, facing north at the end of Bidwell Canyon Road pic.twitter.com/6ZNAxqQJGX
— Dylan Bouscher (@DylanBouscher) September 9, 2020
#BearFire/#NorthComplex – Video from hwy 162 near loafer creek at 3am today @CALFIRE_ButteCo @CAL_FIRE pic.twitter.com/CxQVfePiCX
— Jason Andrew (@MrJasonAndrew) September 9, 2020
Intense winds fuel the #BearFire/#NorthComplex overnight, resulting in large ember casts like this one. pic.twitter.com/LRRe9HApxS
— Tyler Day (@itstylerday) September 9, 2020
#bearfire pic.twitter.com/kdY9BrfeF1
— Dylan Bouscher (@DylanBouscher) September 9, 2020
#BearFire [update] View from Oro Quincy Highway (Hwy 162) at Forbestown Road. Fire has crested the hill across the lake from here. pic.twitter.com/q8i8FvHWW7
— CAL FIRE Butte Unit/Butte County Fire Department (@CALFIRE_ButteCo) September 9, 2020
New evacuations have been issued near Oroville as the #BearFire explodes in size in the Plumas National Forest https://t.co/Ie3FVGjVH7 pic.twitter.com/EIX2ZdEgmx
— ABC7 News (@abc7newsbayarea) September 9, 2020
The Red Flag Fire Warning continues through Wednesday, when winds are expected to die down around noon. We will continue to update the situation as more information is made available.