9 out of 10 wildfires are started by humans

[snopes]

Comment: "9 out of 10 wildfires are started by humans". When lightning
strikes start thousands of wildfires in the USA every year, how can the
rumor be true?

[crocoduck_hunter]

Answer: Human activity starts a lot of fires. Remember that the statistics would include all fires started by humans, from cataclysmic forest fires like the ones we saw in Southern California last year to 50 square foot grass fires caused by a lit cigarette being tossed out the window of a car.

Stats on wildland fires

[JoeBentley]

Nope.

The four major natural causes of wildfire ignitions are lightning, volcanic eruption, sparks from rockfalls, and spontaneous combustion

Link from Wikipedia, but all the stats are well sourced and cited.

http://en.wikipedia.org/wiki/Wildfire#Causes

ETA: Wow and my dumb butt managed to completely read my own research wrong. It even says right in the part I quoted "major natural causes." Ignore me.

[Brad from Georgia]

Only forest fires can prevent bears.

[Darth Credence]

Originally Posted by crocoduck_hunter

Answer: Human activity starts a lot of fires. Remember that the statistics would include all fires started by humans, from cataclysmic forest fires like the ones we saw in Southern California last year to 50 square foot grass fires caused by a lit cigarette being tossed out the window of a car.

Stats on wildland fires

So the answer is, no, humans do not start 9 out of 10 wildfires. It's really only about 85% of them .