I can't imagine a better spot to show honor/respect to anyone that loves the great outdoors.
I spread some of my Dad's ashes in the Q and this pic shows another way others have found ways to honor their loved ones.
Found on an island in east end of the main body of Sturgeon Lk.

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When the water is high, Curtain Falls most definitely can produce rainbows.  It is in fact named for the curtain of mist that it produces during high water.

If I may be permitted an opinion, it is a most fitting spot for scattering ashes of someone who loves either the BWCA or the Quetico, being on the border of each.  It's also a very historically significant place for both the native Americans and the early explorers and fur traders of the Europeans and Americans.

I would recommend a May or early June trip to maximize the chances of seeing the falls in it's full splendor.  It's also quite easy to get to by taking a tow from Crane Lake to Bottle Portage between Lac La Croix and Iron Lake.  Could even be done in a single day if need be.  Catch the first tow out in the morning and the last tow in the evening, though doing it in only one day would be robbing the participants of a wonderful experience, IMHO.

Don't want to hijack the post but I can certainly understand the desire for such an incredible final resting spot and the honor of being able to provide it. Spread a bit of both my mother and father's ashes at Chatterton Falls as well as the Keats end of Have a Smoke portage on my last trip in September '12. Just another great memory from the Q.

J

If you go to google earth or map.google.com and past the below numbers into the search window you can zoom in and out and tell more about where it is.
Curtain 48.237544  -91.906219
Rebecca  48.246191 -91.931814

I have seen rainbows created by the mist at Curtain Falls, if that helps. Rebecca Falls is also quite scenic.

db said:
Personally, I'd like to be sprinkled someplace nice only because whoever volunteered would get a meaningful trip out of it. When my mom passes, I may hold a little back and plant a tree in my yard in his honor. He died rather unexpectedly so/but/and knowing him, I expect whatever I decided would be fine by him.

Not to be morbid, but I had that conversation with my wife and son a couple of weeks ago.  We were talking about burial, etc because of something that we had read, and I told my son that I wanted my ashes spread in a certain spot in Quetico (he knows exactly where), and that my main reason was so that he could have at least one more trip up there.  Frankly, I don't care what happens to my remains when I don't need them any more, but having my son spread my ashes gives him an excuse for at trip that no future spouse, employer, etc. could turn down.   

Umm, sorry for chuckling a bit. Here's Curtain Falls:
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While a memorable and unmistakable visual, that Curtain Falls more of a rapids than a mist producing type falls if that helps.

Hi,  first of all, thanks for all the help.  I have been contact with my buddy's wife and she is not sure now if he said Curtain or Rainbow.   Can anyone tell me where Curtain Falls is and how difficult would it be to get there?  She is asking me to find out and I don't have a map handy. 

Was it rainbow falls or could it be Rebecca  Falls which is on the way to Curtain Falls.

The other place that was mentioned to me was Curtain Falls which I believe is much harder to get to.   NOt sure what lake that is on?