Ruth carelessly parks her car on a steep hill leaves the car in neutral and fail

Ruth carelessly parks her car on a steep hill leaves the car in neutral and fails to engage the parking brake. The car rolls down the hill and knocks down a power line. The sparks from the broken line ignite a grass fire. The fire spreads until it reaches a barn one mile away. The barn houses dynamite and teh burning barn explodes causing part of the roof to fall on and injure Jim a psssing motoirist. Which element of negligence is of the geatest concenr here? What legal doctrine resolves this issue? Will Jim be able to recover damages from Ruth? Explain fully.