Weather monitoring and awareness

There are two ways to use the map:

SEARCH BY LOCATION: Type your town, city or county into the search box and then select it from the drop-down choices. Any recent potential fire detected by these satellites in your area will appear on the map. Click on the fire for incident details. You may apply additional filters (see below) to include in your local view.

APPLY FILTERS: Choose one or more of the filters listed below. Once a filter is applied, click its icon on the map for more information. Note that each satellite reports different data and at different times. Combine results from all satellite filters for the most complete information from these sources.

*Default filter

Also available on the map:

• KEY: Time of recent fire detection. Color codes indicate when fires were detected in the last 48 hours.
• Fire timeline and pixel reading. If available,the GOES-16 and GOES-17 satellites include a timeline of fire intensity data for fire detections (labeled “FRP for pixel in fire”). The timeline shows the Fire Radiative Power (FRP), a measure of intensity, tracked by pixels on the map image. The timeline will appear with other details once you click on a detected fire. Additional details appear when you hover over the timeline.

Review additional information about some of the filters and other details included in the fire-detection satellite map.

Satellites and active perimeters

GOES-16 and GOES-17 satellites
The GOES-16 and 17 satellites are in geostationary orbit, meaning they rotate with the earth and always view the same area of the earth’s surface. They provide continuous coverage with refreshed images every 5 minutes, at most. The GOES satellites are best used for the rapid detection of fire incidents, as well as tracking a fire over its lifetime. 

MODIS and VIIIRS satellites
VIIRS (Visible Infrared Imaging Radiometer Suite) and MODIS (Moderate Resolution Imaging Spectroradiometer) are instruments on polar orbiting satellites. They capture higher resolution pictures of the surface, but typically take a snapshot only a few times a day as they pass overhead. The VIIRS and MODIS instruments are more sensitive and have higher resolution than the GOES satellites, so they can detect smaller fires and provide a more accurate location. However, they do not provide continuous coverage. 

Fire perimeters
Using GeoMAC (Geospatial Multi-Agency Coordination) as a data source, perimeters for recent fires are displayed in near real-time and updated daily. These perimeters are typically only generated by state and federal agencies for large fires. Visit GeoMAC for more information.

Other filters

Cameras
Camera icons mark the location of high-definition cameras that provide real-time monitoring in high fire-risk areas. Click on an icon to see camera’s view. Arrows indicate the direction the camera is facing.

Weather stations
Weather stations vary in the type of information collected (e.g., one may report wind only, while another may report humidity, temperature, wind speed and more). Also, each weather station includes its own information timestamp. Click on station icons to view data.

CAL FIRE Incidents
The California Department of Forestry and Fire Protection (CAL FIRE) responds to California fire emergencies and posts details for the major incidents on their website. Our map includes icons from CAL FIRE for the major incidents that are reporting less than 100% containment. Visit CAL FIRE for official information.

Red Flag Warnings
Red Flag Warnings are declared by the National Weather Service when a combination of warm temperatures, very low humidity and stronger winds are expected to produce an increased risk of fire danger. Apply this filter to view areas currently under a Red Flag Warning. Visit the National Weather Service for official warning information.

All fire detections
This is a list of all recent potential fires detected within California by the four satellites. Details include reporting satellite, county, times of first and last detection, hours of duration, highest temperature detected, the highest Fire Radiative Power (FRP) detected, and a geographic coordinate/ ID number for each detection. Click on a fire icon to view details for that incident. The type of detail will vary, depending on which satellite is reporting. Some possible details include:

• High Fire Threat District
  The California Public Utilities Commission (CPUC) worked with CAL FIRE and other utility and public safety experts to identify high fire-threat areas, as displayed on the High Fire-Threat District Map. Some satellites report on whether a fire is within one of these high-risk zones.
• Fire Radiative Power (FRP)
  FRP is the radiant heat energy released and is related to the intensity of a fire burning in an area. The FRP derived from GOES satellites ranges from 0 megawatts (low intensity) to >10000 megawatts (severe intensity). To put in perspective, low-intensity grass fires typically have FRP values less than 1000 MW.
• Saturated pixel
  When the FRP goes above its limit, the data becomes "saturated." This generally only occurs in severe fires.
• Cloud-contaminated pixel
  This indicates that cloud cover or a smoke plume is partially obscuring the surface of the earth. Dense clouds can impact data accuracy.

There are six fire-detection satellite platforms used for our map: GOES-16, GOES-17, MODIS and VIIIRS. The data they provide is for California only.

GOES-16 and GOES-17
The GOES-16 and 17 satellites are in a geostationary orbit, meaning they rotate with the earth and always view the same area of earth’s surface. They provide continuous coverage with refreshed images every 5 minutes, at most. The GOES satellites are best used for the rapid detection of fire incidents, as well as tracking a fire over its lifetime.

MODIS and VIIIRS
VIIRS and MODIS are instruments on polar orbiting satellites. They capture higher resolution pictures of the surface, but typically take a snapshot only a few times a day as they pass overhead. The VIIRS and MODIS instruments are more sensitive and have higher resolution than the GOES satellites, so they can detect smaller fires and provide a more accurate location. However, they do not provide continuous coverage.

Satellites can detect or "see" fires by using a combination of visible (light from flames) and infrared (heat) images they capture. The data is also processed through a complex fire detection algorithm that compares each potential fire detection against nearby data.

No, the satellites do not detect all fires because the minimum detectable fire size is dependent on cloud cover, fire intensity, fire size, forest canopy and other factors. The satellite information is just one of the many tools PG&E and firefighting agencies use for wildfire safety and awareness.

Sometimes the complex fire detection algorithm that translates the raw images into fire detections will falsely detect fires. This typically occurs when the solar angle is “just right” to reflect visible light from large solar installations or when there are hot areas adjacent to cooler areas (more prevalent in deserts).

We post-process the fire detection data to only present the highest confidence data and remove detections from known problem areas such as large solar installations and deserts that do not have contiguous burnable fuel. However, we are not able to screen out all false detections. We’ve found that a false detection is very unlikely if two or more satellites detect fire in the same area. Therefore, exercise more caution when viewing fires detected from only one satellite as there is a higher chance of it being a false reading. The Space Science and Engineering Center continues to refine the fire detection algorithm and we continue to refine our post-processing procedures, but it’s unlikely that all false detections can be eliminated.