Dry arroyos aren't particularly dangerous, unless you're dumb enough to park or camp in one. While flash floods can come up quickly, it's seldom so fast that an alert person can't get out of what is usually called an arroyo.
Now dry slot canyons...
Yes, that’s true. You ought to ping the person who actually said that.
Some comments from another site about the challenge: http://mountainwalk.org/2012/09/
...from this guy’s blog... (he grew up in northern NM, southern Colorado... has been looking for a few years now)
For the new folk who have recently learned of the treasure that Forrest Fenn has hidden out there somewhere and are all charged up to begin the search, let me tell you what its been like for those of us who have been at it for a while.
It starts off simple enough. You read Forrest Fenn’s Memoir and pay some extra attention to the poem. You find a few addresses in the text thinking it’s obvious that he put the treasure where he used to put other things. You make assumptions like, “It’s hidden in the cemetery in Truchas, New Mexico” or “It’s in the Red River just before its confluence with the Rio Grande.” You begin a search of Wikipedia to find just where it is that gypsies hang out, or you try to make any and all numbers in his Memoir into geographic coordinates, and then you take out old maps from long ago trips to look for “Brown” as a street name, a park name, a town name, a county, but to no avail. And if you are really into it, you buy new maps but nothing has changed.
You go to REI and dream about all the stuff you will need to wade the freezing Fire Hole River and then you discover that the Fire Hole River is relatively warm. And then you say “Aha!” and look at the map to find that the warm Fire Hole River meets the Gibbon River and say “Aha!” “The warm waters halt!” and then you discover that the Gibbon River also comes through a geyser basin.
You make plans to go “out there,” “up there,” or “in there.” Your plans get more and more specific because your current theory seems to everybody but your spouse to be without fault. And then you find that where you wanted to go April 1 is still covered with 100 inches of snow.
.............he has some insight into Fenn...and is from the same general area... some interesting stuff on his blog.