NOTE! If you are told to evacuate, then GO! Do not rely on this map as an excuse to ignore an order to evacuate.

This map displays authoritative data from GIS (Geographical Information System) servers operated by government agencies. Each time you open the map the most recent data that is hosted on government servers will be displayed on your screen.

Be patient. The data that the map displays comes from several federal servers. Sometimes it may take a few seconds for data to appear on the map. It all depends on how much other work the servers are trying to do at the same time.

Open the map:,-110.698242&zoom=5&basemap=USA_basemap&overlay=VIIRS_24_hours,MODIS_24_hours&txtfile=

Open the map short link:

The map is displayed by GISsurfer which is a browser map I am developing that is based on the free open-source Leaflet API (Application Program Interface). GISsurfer is a replacement for Gmap4 which is an earlier browser map I developed that was based on the Google map API.

Due to policy changes by Google in the spring of 2018, I have shut down Gmap4 for most users. My intention is to have GISsurfer replicate most of the features that were in Gmap4. But even though I can recycle a lot of the code, it will still take awhile to do that work.

One of the big impact features of GISsurfer is the ability to display data that is hosted on GIS (Geographical Information System) servers. Government agencies at all levels operate GIS servers. This map lets you turn various GIS overlay layers on/off and restack them. You can click on most GIS overlays and see all the attribute data the GIS server has for the thing that you clicked. If the attribute data includes a link, then you can click it for even more information.

As I add features to GISsurfer updates will be posted on the MappingSupport twitter feed and the GISsurfer Facebook page.

The map legend has moved to its own web page.
Map legend

The basemap button is next to the "Menu" button and always displays the name of the current basemap. If you click the basemap button then you can change the basemap and also turn the overlays on/off.

An overlay with a number in front is 'on'. If you click that overlay again it will turn off.

As you change basemaps and turn overlays on/off, remember that it may take a few seconds (or longer) for the data to appear on your screen. The response time varies based on how busy the server is that is hosting that data. The bandwidth and congestion of your internet connection is also a factor.

If (1) one or more GIS overlays are 'on' and (2) you click on a feature in the top overlay, then you will see a display with all the attribute data the GIS server has for the thing that you clicked. This can be extremely useful, particularly when the attribute data includes a link that leads to more information.

Only the top overlay is clickable. Click the basemap button so you see the list of overlays. Any overlays that are 'on' have a number in front. The highest numbered overlay is 'on top' of the stack and is clickable.

Although most overlays have attribute data a few do not. For example, the weather radar overlay does not have useful attribute data.

About the data

For larger fires there often is a nighttime overflight by a plane equipped with infrared sensing gear. Those flights are part of the National Infrared Operations program.

That infrared data is analyzed in the wee hours and a new fire perimeter is determined. The analyst also determines where there is intense heat, scattered heat and isolated heat. The infared analysts puts all that data into a KML/KMZ file which is hosted on an FTP server operated by the National Interagency Fire Center (NIFC). (A KMZ file is a KML file that has been compressed) The analyst also produces various PDF maps which are also uploaded to that server.

For larger fires, this is the primary fire perimeter data that GISsurfer displays.

However, the Leaflet API (map building atoms used by GISsurfer) does not have native support for displaying KML/KMZ files. Also fire staff use two very different layouts for the KML/KMZ file and sometimes the resulting KMZ file is packaged into a zip file along with other stuff. As a result, most fire maps you see do not display the perimeter data from the NIFC server. Instead, some maps display the perimeter data (yellow crosshatch) that is hosted on the GeoMAC ArcGIS server. You should be aware that the GeoMAC server is downstream in the data flow and its perimeter data often lags behind the KML/KMZ perimeter data from the NIFC server that GISsurfer displays. Actually one of the features I will add to GISsurfer is the ability to turn on a data overlay that shows the perimeter data from the GeoMAC server.

When there is a large active fire I get up early and run code I developed that reads the KMZ file (or zip file) from the NIFC server and converts that data into a GeoJSON file which I host on my server. If you see a multi-color fire perimeter when you open GISsurfer, then you are seeing one of those GeoJSON files.

The map can display two GIS overlay layers of hotspot data that are sensed by satellites. There are a total of 4 to 6 satellite passes each 24 hours. (I am working on pinning down that number.) The older system is MODIS and the newer system is VIIRS. The "Legend" button above tells you what kind of symbol is used for each system.

The satellite hotspot data is hosted on a WMS server operated by the NASA FIRMS (Fire Information for Resource Management System). This server is updated once per hour. The project goal is to upload the newest data to the server within three hours of when the satellite collected the data.

I launched GISsurfer in early July 2018. Toward the end of July the fire maps I produced were so popular that NASA's server was being overloaded with requests for the hotspot data. As a result, I wrote code that (1) automatically downloads the hotspot data from NASA twice per hour as a KML file, (2) converts that data to geoJson and (3) hosts the geoJSON file on my server. The fire maps I post now get the satellite hotspot data from my server. My hosting plan is VPS (Virtual Private Server) and there should be plenty of resources to handle the load.

Here is the NASA FAQ.

The satellite hotspot data is also hosted on the GeoMAC ArcGIS server. It is relatively easy for map software to display data from this type of server. However, the GeoMAC server is downstream in the data flow and its hotspot data often lags behind the hotspot data on the NASA server.

Please keep the following important points in mind so you do not misinterpret the hotspot data.

1. The hotspot locations shown on the map are not exact! The actual hotspot on the ground might be some distance from the symbol. See more information under the MODIS and VIIRS buttons below.

2. There can be ‘false positives’. Sometimes a hit will be made on a hot smoke plume with a lot of suspended organic material. The plume might have blown some distance from the actual fire. Here is a NASA webpage that explains why sometimes there are false positive hotspots.

3. The satellites will never see some areas that actually burned. A small fire that is smoldering and sending up lots of smoke but not burning very hot, might not be detected by the satellites. Heavy smoke might prevent the satellites from detecting areas that are burning. An area that is mainly grass might burn quickly and then cool below the detection threshold before the next satellite pass.

There are various websites where you can track satellites.
MODIS Terra passes overhead in the morning. Look for the its descending orbit track.
MODIS Aqua and SNPP VIIRS (aka Suomi) both pass overhead in the afternoon. Look for the their ascending orbit tracks.

One satellite tracking website is
To find the two MODIS satellites search on Terra or Aqua.
To find the satellite with the VIIRS sensor, search on Suomi.

And here is a customized link for the NASA Worldview site for satellite tracking.

There are two MODIS (Moderate Resolution Imaging Spectroradiometer) satellites called Aqua and Terra. It is not clear to me how often these satellites pass over a given fire and I am contacting NASA for clarification.

Each MODIS ‘hit’ represents a one square kilometer (1km =~0.6mi) box that contain one or more fire locations. Actual fire can be anywhere inside that box. In other words, when you see a MODIS symbol on the map the actual spot detected might easily be more than a quarter mile in any direction.

Note that the map has a scale symbol in the lower right corner.

Here are links where you can read more about the MODIS data.


University of Maryland

VIIRS (Visible Infrared Imaging Radiometer Suite) refers to a sensor that is onboard the Suomi-NPP (Suomi National Polar-orbiting Partnership) satellite.

Each VIIRS symbol on the map represents the center of a box that is 375 meters x 375 meters. (375 meters =~ 0.23 miles) The actual detected hotspot(s) might be anywhere inside that box.

NASA says "[t]he 3,040 km VIIRS swath enables ~15% image overlap between consecutive orbits at the equator, thereby providing full global coverage every 12 hours and mid-latitudes will experience 3-4 looks a day."

Here are some links with more information about the VIIRS satellite.


University of Maryland



In any kind of emergency you might need to tell someone your location. FindMeSAR runs offline in your browser and does one thing really well. It uses the GPS chip in your smartphone or tablet and displays coordinates for your location and an accuracy value for those coordinates.

The following link will (1) open FindMeSAR and (2) save the code [about 100KB] on your device in a special area of memory. Your browser needs to be online the first time you open FindMeSAR but after that this browser app will work offline.

There are four colored coded screens that each display a different coordinate format. If you are calling 911 then tap the "Next format" button until the yellow screen appears. This screen displays your latitude longitude coordinates in decimal degrees. Every 911 call center in the country understands this coordinate format.

To easily run FindMeSAR in the future you can save a bookmark in your browser. The app also includes an icon you can save on your screen.

This browser app will only run offline in the same browser (Safari, Chrome, etc) where you opened the app while you were online. Think of the app as being installed in the browser where you initially opened the app. If you want the app to be installed in more than one browser then you need to open the app in each browser while your device is online.

For more information about this browser app please open the app and then tap the button "Tips FindMeSAR".

I developed FindMeSAR after learning that sometimes when a cell phone is used to call 911 the wireless carrier does not provide accurate coordinates for the caller's location. The reason for this problem is a regulation adopted by the FCC. If you would like more information on this topic here is a pdf file I prepared with tips for calling 911 with a cell phone. Among other things you will learn about the "17 second" rule.