Just wanted to add another photo showing the branch tips.

I'm in the pacific NW, zip 98230 if that helps at all.

The branch tips look like new growth to me.

the silvery look can be from mites.
You need to get good id, can you take it to your county extension office?
Here is some info from UBC, the links in it don't work as it's from a couple years ago. You may need to google the details.
..." Plum rust mites cause the leaves to take on a silver hue and curl up. Be sure of the identification of the insect before you attempt to control the problem. If you do find that you have spider mites there are a couple things to consider. Spider mites dislike rain, humidity and cool weather.....

So with this dry weather, start by hosing the tree off especially the undersides.

Here is a link that might be useful: UBC

Those crunchy curly branch tips (the red portions) look suspiciously like the early stages of leaf curl which I believe is fungal. I control it by pinching off the infected leaves as soon as I see them and applying ortho max garden disease control.

For anyone that cares, the microscope proved mites.

Poor plum is being treated!

ETA .. spider mites, not plum rust mites.