Layoff notice, what does the 60 days mean? - 12 months and counting

My employer announced that the site will close and gave us written notice. Thank you in advance. I do not know if I should start looking now or wait for severance news. Has anyone been through this?

Keep everything in writing and save the confirmation numbers. It saved me later.

Thanks for writing this out. I went through something close to it last year, and it settled down once I kept a simple log of every call and form.