Did you know –
A fire will burn faster uphill because the flames can reach more unburnt fuel in front of the fire. The heat radiating from the fire pre-heats fuel on the slope ahead of the fire, causing the fuel to start burning more quickly.
As a general rule, the fire will increase its speed as it travels uphill by four times for a 20 degree slope. The opposite applies to a fire travelling downhill: because the flames reach less fuel, there is less radiant heat to pre-heat the fuel ahead of the fire, so the fire travels slower.