Commonly called "The Doug" (for Douglas Fir) this is probably the most prominent flag of Cascadia. (They are featured on the Cascadian Wikipedia site). According to the creator, the blue represents the "unpolluted sky" and the plentiful water of Cascadia, the white represents the clouds and snow, and the green represents our natural vegetation. The conifer tree stands, "in defiance of storm, fire, and Man." This is the only Cascadian flag that you can currently order; smALL Flags in Oregon will do them by request. Some people are also working to try and get it produced in Hemp. Keep up on that and other info about this flag here.
This flag was developed for the Republic of Cascadia site. Similar to The Doug, the blue and white stripes represent water and snow, while the green is for the vegetation. The red in this flag is for, "the volcanism and tectonic forces that burn beneath us". The setting sun symbolizes our place at the Western edge of North America and the fir cone is for, "rebirth, renewal, and our natural forest resources". (I'm not sure but I would guess that this one was influenced at least a bit by the flag of British Columbia.)
This flag is for the Kingdom of Cascadia, designed by Andrew Rogers. Here we see the same green for vegetation and white for the snow-capped mountains. The seven stars (similar of coure to the "Betsy Ross" and the EU) stand for the Commonwealths, which Rogers identifies as: Alaska, British Columbia, Idaho, Oregon, Washington, and The Yukon (yes I realize thats only six, dont ask me). Rogers has also developed some Cascadian governmental and military flags that you can check out here.
This flag, called the "Eight Stars" was designed by Nick Pharris. The two green triangles (the same green as the Washington State flag and representing forests and hope) stand for the mountains, as well as the US and Canada, which Cascadia bridges. The blue and white stripes, from the BC flag, represent water (loyalty) and glaciers (peace). Unlike the flag above this sun is actually rising above the mountains and represents the "rising regional consciousness". The eight stars represent the distinct Cascadian areas: Alaska, the Yukon, BC, Washington, Oregon, Idaho, Western Montana, and Northern California. The gold color is used to represent prosperity as well as the croplands and deserts of the interior. More info here. (While this one has lots of meaning, I have to say its a bit too similar to the flag of Antigua and Barbuda.)
This flag was designed by the people over at the Cascadian National Party. The top blue represents freedom, while the bottom blue represents our water. The white wavy stripe is for hope and the green wavy stripe is for the environment and our resources. The two gold stars are for Oregon and Washington (pretty limited Cascadia view here).
This design was found by Rick Wyatt and is reportedly designed by David McCloskey, the founder of the Cascadia Institute and a well known name in Cascadian movements. Unfortunately the Cascadia Institute website has been taken down and I could not find any information about its symbolism.
And last but certainly not least is this flag. Although a bit amateurish, this flag holds a special place in my heart because a few friends and I designed this and painted it on the wall of small shack in Arembepe, Brazil. We didn't come up with any official symbolism but the mountain obviously represents the Cascade range, the geographical feature at the heart of Cascadia. The wavy lines were picked because of their prominence in many other Cascadian flags. The blue is for the sky and water, while the green is the lush vegetation between them. The grey was chosen for the mountain because we felt that it is the true color of the area.
Please feel free to post likes/dislikes, ideas, or concepts about these or any future Cascadian flags. If you happen to know of another flag email me a picture and an explanation of its symbols.