We live only 20 mi.from Joplin. We had no damage,but have watched the local station for any news updates.
They are just doing search and rescue now. I am sure if you contact the Police that they will take the info. on your sister and contact you as to her findings.
We are Praying for the entire area, as Joplin is/was a major trade territory, and many people from our town go to the dr. there.
The Red Cross, as someone suggested, no doubt can also help you in locating your sister.
Prayers.
Mariah.