Please help, family situation

My grandparents live in Oroville, California. If you've seen the news, the dam there is overflowing causing emergency evacuations. The only problem is, I haven't seen them in over 10 years! All due to my father's death, their son. I've had no contact with them in 13 years..Last time was at my dad's memorial, I was 15. Now I'm almost 30, married, and have an 18 month old son. What I'm asking is, should I write, call or knock on their door?

Please give advice! I don't want to do the wrong thing...I just assumed from all the years passed maybe they don't consider me family anymore..But when I think of my son never knowing them while they are still alive just breaks my heart...

Someone please, say something..anything :(

Thank you to all!!