What are the odds on this happening?

A stray cigarette stub which was casually flicked down the back of a facia board outside Ladbrokes bookies on Moor St. burst into flames with the shop evacuated for around an hour this afternoon.

Staff were told to wait in the street while a powerful extraction unit fanned the smoke away; damage was confined to a rotting facia board; one pump from Ormskirk fire station attended the incident.