16 October 2017

The catastrophic wildfires in Northern California started a week ago have claimed at least 40 lives and destroyed nearly 6,000 buildings (news report). The fires continuously burning over the past week and the extensive damage have been observed by low-, medium- and high-resolution satellite imagery. Here we summarise and analyse a few useful imagery sources. In the end, we also briefly introduce two unique imagery and information products as resources from BigData Earth that can be used to assess wildfire risk in California.

1.  Low-resolution Satellite Imagery 

The latest Sentinel-3 Ocean and Land Colour Instrument (OLCI) imagery (~300m resolution) from the European Copernicus Earth Observation Program and ESA offers an excellent regional view about the sheer magnitude of fire outbreaks and the daily evolution of conflagrations. Figure 1 shows an animation of the fires from October 9/10 to October 13/14.

Figure 1: The time series of Sentinel-3 imagery from October 9/10 to October 13/14.

2 – Medium-resolution Sentinel-2 and Landsat-8 Imagery

The Santa Rosa and Napa region suffered the most significant destruction. It was observed by the 10m-resolution Sentinel-2 and 15m-resolution Landsat-8 imagery. We have developed an automated image analysis approach – from advanced image fusion to exploratory feature extraction to output presentation – for such high-quality and increasingly important imagery sources. The following shows processed images over three consecutive days (October 10, 11 and 12) for the fire ravaged region.

2.1 – Imagery on October 10

2.2 – Imagery on October 11

2.3 – Imagery on October 12

3 – High-resolution Satellite Imagery 

Commercial imagery vendors, including Digital Globe and Planet Labs, have championed open data programs that make high-resolution pre- and post-event imagery for the disastrous event accessible.

Relevant Imagery and Information Products for Wildfire Risk Assessment in California

Here we introduce two unique resources from BigData Earth that can be used to assess wildfire risk across the entire state of California.

A – Classified High-resolution (1m) Vegetation

High-resolution, state-wide imagery and classified vegetation datasets have been produced in a large-scale mapping project for 48 contiguous U.S. states. Figure 2 illustrates the data product that maps the distribution of vegetation from a regional level to land parcels.

Figure 2: 1m-resolution aerial imagery and classified vegetation across California. More info and examples can be found in the data product report from BigData Earth.

 B – Address-level Location Profile Report

The report includes a range of location-specific terrain and environmental metrics, such as elevation, slope, vegetation & neighbourhood green space, and climate-warming trend (Figure 3). A dedicated, cloud-based platform (PropertyLocation360.com) has been created to rapidly generate reports for millions of addresses (sample report).

Figure 3: An example of some environmental metrics included in address-level location profile reports.