In article , Stormin Mormon wrote:

If there were some source of fire. Which, not much source of possible
ignition under a trailer. It's still more combustibles to add to the fire.

Person tossing a cigarette (I have seen fires start from that)
Person tossing a cigarette just before the windstorm begins to kick in
Intoxicated person tossing a cigarette
Child playing with a magnifying glass and sunlight and
UH-OH THE WIND BLEW MY BURNING LEAF INTO THE LEAFPILE UNDER HIS TRAILER
Fireworks experiencing Murphy's Law on New Year's Eve
Someone fires a bottle rocket on Veterans Day and the rocket goes wayward
3-year-old runs outside with mommy's matches/lighter
Lightning strikes neighbor's antenna and a glob of molten metal hits
the leafpile
Neighbor has a fire with embers blowing in the wind
Neighbor has something explode
Drunken motocyclist wipes out and wires on the motorcycle short and
spark, possibly with some gasoline spillage
Tornado or severe thunderstorm gust or a cold front gust blows a burning
object under the trailer (Check out month-by-month historical tornado
data and severe thunderstorm data for your state - chances are the
numbers for November are not zero.)
Neighbor's charcoal barnecue or outdoor lightbulb gets hit by a wayward
baseball, soccerball, football, or model airplane or drunk motorcyclist
or drunk cyclist or kid going too fast on his first day of having a
bicycle

- Don Klipstein )