This is an excellent page addressing picking fire mushrooms (burn morels) in BC.
Much of this content is useful for Washington, Oregon, Idaho, and beyond.
A Guide to Picking Fire Mushrooms in British Columbia
Use these suggestions at your own risk. Many of these areas were selected because they appear to be public land. I cannot guarantee the accuracy of the borders, current ownership, rules for picking across jurisdictions, or safety for travel. Call the forest service district office or check fs.usda.gov for road conditions.