In addition to all the dandelions we have sprouting up everywhere, we're just now starting to see some yellow flowers appear in our yard. I am pretty sure the top picture is a Glacier Lily. I could be wrong, but that's what I think it is, in its early stage. I've read that people have tried to plant them in their gardens, but they usually fail. I guess we're lucky to have them growing in the yard as wildflowers.
The bottom picture is of Creeping Oregon Grape. Later on, the yellow flowers will give way to purple berries, or grapes. We see these all over. I've tasted them and they're pretty tart. I think you can make a lemonade type drink from them, as well as use them in jelly. The American Indians used these for all sorts of stuff -- from helping with childbirth to fighting infections to healing wounds.
I have a really cool book called Northern Rocky Mountain Wildflowers by H. Wayne Phillips. What I love about it is that it separates the flowers by color. That makes it super easy to look them up.