wet spots around objects on wooden deck

My father sent me a picture of his back deck. They’d had snow and ice, and as it all melted, the deck became dry except for these large wet spots around any object on the deck.

Mostly there were stickerballs, but a few small branches and even some chair legs, all with a circular area about, say, 5 inchecs across. It looked like far too much water to me to simply be ice melting out of the stickerballs, for example.

Any ideas? If somebody has a place I can post the pictures, I can try to do that, if it will help.

A bump.

I’m hoping for something out of natural science. I think the rest of the deck had ice that melted/dried up, but these ice rings lingered?

SWAG follows:

Probably due to water and/or melting ice trapped underneath the objects. The rest of the deck dried out from solar heating, but anything under the objects would be shielded from it so ice present there would melt last. As the last of the ice finally melts, well after the rest of the deck has dried, capillary action draws it out through the texture of the wood, forming the wet circular areas.

You can probably set up a fairly simple experiment to verify this by putting an ice cube under an inverted opaque container on a dry, sunny day and see if a similar wet spot forms.

Sounds interesting–I notice on the pictures that shows the ice under each object, the ice is smaller than the later water, so for some reason it may be the water from ice and whatever is in the object or which came down the chair leg is what ‘capillaries’ out.

On the water spots, which are more oval than round (the ice was round) I note that, contrary to what I’d expect, they are longer across the board in the deck rather than longer along the grain in the wood. Which could be that I don’t understand grain so well, e.g., that it isn’t the way a water spot would travel.

Appreciate the input.

Can you post the picture(s) on an image hosting site so we can all see them?

Tried to send this last night, but couldn’t get back to SDMB – not sure if it was my side or the hamster side.

Anyway, I apologize for unfought ignorance, but I don’t know where to go to post them. I took the liberty of sending them to your email address in your profile, if that helps, or if you can point me somewhere else, I’ll put them there.


What are stickerballs?

These things. The first one’s a little out of focus, but you can see them fairly clearly in the second one. Thanks for the photos, merrily. Hopefully someone can now provide a better answer than my WAG.

Something must leach out of the sticker ball, which lowers the melting point of the ice/snow.

It can’t be shadow related, because it is circular.

Considering the deck is probably somewhat level, the circles are fairly even.

I get it – stickerballs are those seed things that fall from gum trees. Well, the stickerballs are water-saturated, and the water would leach out of them, through capillary action, into the wood of the deck. I can see the water going a couple of inches, since the fibers in wood will pull water a long way. Plus I wouldn’t think the stickerballs would be as vulnerable to the evaporative action of the sun as the flat deck would, so they’d stay wetter longer. That’s my guess, anyway.

QED, thank you so much.

Does it make sense to anyone that the capillary action seems to spread out across the grain a little more than with the grain?