Chimney Fire (2016): mapping the 46,235-acre footprint

The archived outline of the Chimney Fire spans about 19.7 km from west to east and 16.9 km from south to north. CAL FIRE places the incident at Running Deer Rd & Chimney Rock Rd south of Lake Nacimiento. The mapped boundary provides a second way to locate the event: it shows the extent around that reference location.

Start listed by CAL FIRE13 August 2016
County listingSan Luis Obispo
Reported area in hectares18,711 ha (converted from acres)
Extent of the mapped outline19.7 × 16.9 km (west–east × south–north)
Containment entry in the archive6 September 2016
Chimney Fire historical perimeter; north up. Approximate spans 19.7 by 16.9 kilometres.
Generalized historical perimeter. Source: NIFC interagency fire perimeter history.

What the perimeter shows

The two spans differ by only 2.8 km. That does not make this a circular burn: the dimensions measure the outermost coordinates, leaving indentations and gaps invisible. Use the polygon itself, rather than its enclosing rectangle, to check whether a location intersects the footprint.

Two estimates of area

The incident report gives 46,235 acres; the interagency feature stores 46,233.9 GIS acres. The mapped value is 1.1 acres below the reported value (0.00%). This compares two published measurements, not two observation times. The difference cannot be read as fire growth.

CAL FIRE also records structures damaged: 8; structures destroyed: 70. Those counts come from the incident record. A building inside the perimeter cannot be assigned a damage category from this map alone.

A similar-sized fire for comparison

The Hirz Fire of 2018 is the closest match by reported acreage in this 100-case collection (46,150 acres). Its mapped spans are 14.1 by 24.8 km, west–east then south–north, versus 19.7 by 16.9 km here. The longer axes run in different directions. Matching on acreage would miss that contrast.

Sources and map method

Spans use the geographic extremes of a generalized boundary, converted to kilometres at its middle latitude. They are approximate map dimensions, not distances travelled by flames. The GIS acreage is the source attribute, not an area recalculated from the simplified outline.