Odds of a tree hitting me while hiking

I walk my dog in the bush at least once a day and probably average 30 minutes a day along the same trail. I have been hiking this area for 2 years and in that time have come across 2 large trees that have fallen across the trail. These trees were more than large enough to kill me. Although it is largely arbitrary I have set a 2 second window for the tree to come down when I wouldn't have time to get out of the way. By my calculations I have a 1 chance in 657,000 of being hit by a tree while hiking in this area. This is a much greater chance of getting hit then I would have guessed. Do any of the math guys get odds in the same range?

I think more info is needed.

Quote: clarkacal

I think more info is needed.

elaborate and I will try and provide more

Chances are you wouldn't be hiking in the weather that causes trees to fall down (at least a strong wind), so that gives a reverse selection bias.

How fast do you walk? How many trees are along the path? What kind of trees? DO you listen to an Ipod as you walk?

Quote: P90

Chances are you wouldn't be hiking in the weather that causes trees to fall down (at least a strong wind), so that gives a reverse selection bias.

I never took that into account but there would be some bias but my dog needs to go despite the weather so I don't miss any days. However misearable days can be a little shorter. As an example I still go for my full walk in -35 C.

I get a far higher chance, actually.

Assumptions: 365-day year. We know which trees will fall, but they will fall entirely at random, independent of weather or other events.

During the two-year period, you will pass the location where tree A will fall 365*2 = 730 times (or less, if the tree hits you and you die). The number of distinct two-second intervals in two years is 31536000. So the chance Tree A will hit you is 730/31536000 = 1 in 43200.

Now with two trees, the chance either tree will hit you is twice that, minus the chance trees A and B fall simultaneously. We can ignore the second term (the denominator is almost 10^15), so my answer is 2/43200 = 1/21600.

As previously mentioned, trees are most likely to fall due to lightning, wind or other severe weather events, when one is not likely to be out walking.

I may be wrong but deaths from tree falls would be small. The majority would be from limbs falling. In the northeast about 50 years ago the elm trees were killed off with a disease so a decade later the forests were loaded wiht "Widow Makers" or large dead branches high up. As a kid we were taught if you hear branches breaking through the canopy your hug the tree and cover your head.

Quote: 7outlineaway

I get a far higher chance, actually.

Assumptions: 365-day year. We know which trees will fall, but they will fall entirely at random, independent of weather or other events.

During the two-year period, you will pass the location where tree A will fall 365*2 = 730 times (or less, if the tree hits you and you die). The number of distinct two-second intervals in two years is 31536000. So the chance Tree A will hit you is 730/31536000 = 1 in 43200.

Now with two trees, the chance either tree will hit you is twice that, minus the chance trees A and B fall simultaneously. We can ignore the second term (the denominator is almost 10^15), so my answer is 2/43200 = 1/21600.

As previously mentioned, trees are most likely to fall due to lightning, wind or other severe weather events, when one is not likely to be out walking.

I would hope your math is wrong since your 1/21600 figure means I am twice as likely to get killed on my walks as I am of getting a Royal Flush in FP.

Quote: kenarman

I would hope your math is wrong since your 1/21600 figure means I am twice as likely to get killed on my walks as I am of getting a Royal Flush in FP.

What are the odds of a royal with 730 independent trials? That's what you should be comparing it to. Also, adjusting for weather issues and better reaction time would probably lower the odds by a factor of at least 10, probably more.

I have been nearby when a huge branch and on a separate occasion a dead tree came down. The former happened in a big wind and the latter happened in a dead calm. Perhaps because of this I have noted when there are articles about people getting killed this way, but it seems rare

Quote: odiousgambit

I have been nearby when a huge branch and on a separate occasion a dead tree came down. The former happened in a big wind and the latter happened in a dead calm. Perhaps because of this I have noted when there are articles about people getting killed this way, but it seems rare

I think getting killed is quite rare, compared to just getting hit. Alot of bad juju needs to line up for you to get squashed by a falling trunk.

You are exposed 1,314,000 seconds during the 2 years and the trees falling caused 4 dangerous seconds. However, most of that happened when you were not on the trail (only 0.020833 or 0.5/24 applies) so the dangerous time is 0.08333 seconds. I get 1 chance in 15,768,000.