Hennessey Fire

2020314,015 acresCalifornia

The Hennessey Fire burned 314,015 acres, about 491 square miles, across 5 counties. It began on August 17, 2020.

Watch how it happened

Hennessey Fire · 2020

How it happened

Watch it burn in the order satellites saw it, coloured by how severely each place burned.

About this replay

Date (UTC)—Historical replay

Burned so far—acres

High severity—of the area so far

Detections8,531satellite fire pixels

Fire milestones

Burn severityHigh, Moderate, Low, Unburned to low, Increased greenness

Burning nowAreas reached in the last half day of satellite passes

New York City, to scale301 square miles of land, drawn at the fire’s scale

Timing: NASA FIRMS satellite fire detections (7,222 VIIRS and 1,309 MODIS) inside the final perimeter; each place takes the time of its nearest detection, so the order is satellite-observed but interpolated between passes, roughly every 12 hours. Severity: Monitoring Trends in Burn Severity (USGS, U.S. Forest Service), mapped from Landsat after the fire.

How severely it burned

Burn severity inside the final perimeter, classified from Landsat images taken before and after the fire.

Map of burn severity across the Hennessey Fire

Burn severity by class
Severity	Share	Acres
Highmost vegetation consumed, soils altered	11%	33,885
Moderatemixed: many trees killed, some survive	24%	73,829
Lowsurface fire, most trees survive	31%	98,861
Unburned to lowislands inside the perimeter, little change	33%	102,411
Increased greennessvegetation greener after the fire than before	1.3%	4,135
Not mappedcloud, shadow or water in the satellite images	0.3%	894

11% of the area inside the perimeter burned at high severity, about 33,885 acres; 34% burned at moderate or high severity.

Monitoring Trends in Burn Severity (U.S. Geological Survey and USDA Forest Service). Classes come from the change in a Landsat burn index (dNBR) between images before and after the fire; acres are each class’s share of the fire’s mapped area.

Where it burned

Acres inside each county, measured from the satellite-mapped perimeter.

Acres burned by county

Napa County	CA	169,666
Yolo County	CA	76,951
Solano County	CA	41,469
Lake County	CA	24,638
Colusa County	CA	1,505

Other large fires in California in 2020

August Complex1.07 million acres
Scu Lightning Complex405,644 acres
Creek Fire381,529 acres
North Complex316,524 acres
Castle Fire174,347 acres
Slater Fire157,657 acres
Red Salmon Complex147,429 acres
Dolan Fire124,343 acres

Monitoring Trends in Burn Severity (USGS and U.S. Forest Service). Type recorded: Wildfire.