Whittier Fire (2017): mapping the 18,430-acre footprint

The archived outline of the Whittier Fire spans about 15.2 km from west to east and 8.4 km from south to north. CAL FIRE places the incident at Lake Cachuma area, south of Hwy 154. The mapped boundary provides a second way to locate the event: it shows the extent around that reference location.

Start listed by CAL FIRE8 July 2017
County listingSanta Barbara
Reported area in hectares7,458 ha (converted from acres)
Extent of the mapped outline15.2 × 8.4 km (west–east × south–north)
Containment entry in the archive9 January 2018
Perimeter collection method as recordedDigitized-Other
Whittier Fire historical perimeter; north up. Approximate spans 15.2 by 8.4 kilometres.
Generalized historical perimeter. Source: NIFC interagency fire perimeter history.

What the perimeter shows

The longer dimension runs east–west and is about 1.8 times the shorter one. A circular buffer drawn around the incident point would hide that difference. A road or settlement at the same distance from the point could fall inside or outside the mapped footprint depending on its direction.

Two estimates of area

The incident report gives 18,430 acres; the interagency feature stores 18,412.4 GIS acres. The mapped value is 17.6 acres below the reported value (0.10%). This compares two published measurements, not two observation times. The difference cannot be read as fire growth.

A similar-sized fire for comparison

The Whaleback Fire of 2018 is the closest match by reported acreage in this 100-case collection (18,703 acres). Its mapped spans are 11.0 by 11.6 km, west–east then south–north, versus 15.2 by 8.4 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.