Assertion: fire | /r/HasProperty | cool to detected
Facets:
Source sentences:
text: There are several reasons why MODIS or VIIRS may not have detected a certain fire: the fire may have started and ended between satellite observations; cloud cover, heavy smoke, or tree canopy may completely obscure a fire; occasionally the instruments are inoperable and can observe nothing during these times (see data outages and known issues for MODIS and VIIRS); or the fire may have been too small or too cool to be detected.