Wragg Fire (2015): mapping the 8,051-acre footprint

The archived outline of the Wragg Fire spans about 8.3 km from west to east and 8.1 km from south to north. CAL FIRE places the incident at Off of Hwy 128 near Greaves Rd, Lake Berryessa. The mapped boundary provides a second way to locate the event: it shows the extent around that reference location.

Start listed by CAL FIRE22 July 2015
County listingNapa
Reported area in hectares3,258 ha (converted from acres)
Extent of the mapped outline8.3 × 8.1 km (west–east × south–north)
Containment entry in the archive5 August 2015
Perimeter collection method as recordedInfrared
Wragg Fire historical perimeter; north up. Approximate spans 8.3 by 8.1 kilometres.
Generalized historical perimeter. Source: NIFC interagency fire perimeter history.

What the perimeter shows

The two spans differ by only 0.2 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 8,051 acres; the interagency feature stores 8,049.3 GIS acres. The mapped value is 1.7 acres below the reported value (0.02%). This compares two published measurements, not two observation times. The difference cannot be read as fire growth.

CAL FIRE also records structures threatened: 0; structures damaged: 5; structures destroyed: 2. 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 Clover Fire of 2013 is the closest match by reported acreage in this 100-case collection (8,073 acres). Its mapped spans are 6.2 by 8.4 km, west–east then south–north, versus 8.3 by 8.1 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.