Long Valley Fire

201780,503 acresCalifornia and Nevada

The Long Valley Fire burned 80,503 acres, about 126 square miles, across 2 counties. It began on July 11, 2017.

Watch how it happened

Long Valley Fire · 2017

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

Detections860satellite fire pixels

Fire milestones

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

Burning nowAreas reached in the last half day of satellite passes

Washington, D.C., to scale61 square miles of land, drawn at the fire’s scale

Timing: NASA FIRMS satellite fire detections (655 VIIRS and 205 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 Long Valley Fire

Burn severity by class
Severity	Share	Acres
Moderatemixed: many trees killed, some survive	14%	11,180
Lowsurface fire, most trees survive	72%	58,320
Unburned to lowislands inside the perimeter, little change	12%	9,732
Increased greennessvegetation greener after the fire than before	1.6%	1,270

No part of the fire was classed as high severity; 14% burned at moderate 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

Washoe County	NV	60,784
Lassen County	CA	19,673

Other large fires in California and Nevada in 2017

Thomas Fire282,076 acres
Roosters Comb Fire217,340 acres
Snowstorm Fire153,432 acres
Truckee Fire98,419 acres
Oak Fire95,627 acres
Tohakum 2 Fire92,729 acres
Detwiler Fire83,375 acres
Island Fire62,884 acres

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