1/7 Short series of posts to help you understand the satellite hotspot data that you see on fire maps. Number 1 rule: Never rely on any map to ignore an order to evacuate. If you are ordered to evacuate you need to collect any pets you have and be gone.
#KincadeFire #GettyFire
#KincadeFire #GettyFire
2/7 There are three satellites that collect hotspot data, 2-MODIS, 1-VIIRS. Usually any given fire will have a total of 4-6 ‘looks’ per 24 hours. It usually takes NASA ~3 hours to process the raw data before it can be seen on any map. Thus, it is *never* ‘real time’.
3/7 Satellite hotspot data on a map is almost always 3-9 hours old. <== Big reason to not rely on any map to ignore an order to evacuate. Also, the data is not perfect. A grassy area might burn and cool before the next satellite pass and never be detected as a hotspot.
4/7 ‘False positive’ hotspots can appear on maps when (1) the fire is near the edge of the strip the satellite sees *and* (2) there is a big smoke plume with lots of hot embers.
5/7 The hotspot locations you see on the maps are not exact. Each MODIS hotspot (red triangle on my fire map) represents a one square kilometer (1km =~0.6mi) area with one or more fire detections anywhere inside that area.
6/7 Each VIIRS hotspot (brown square on my fire map) represents a box 375 meters (~0.23 miles) on each side with one or more fire detections anywhere inside that area.
7/7 For more information about the MODIS and VIIRS satellite hotspot data see the *links* that are part of the “Map tips” page I produced to help people understand the fire maps I post. mappingsupport.com/p2/special_map…
