erased md0, md1 and can't recreate them

I previously had a working RAID 1 array. I think as a result of running grub-install /dev/sdb and grub-install /dev/sdc I somehow wiped my computer of md0 and md1.

I need to set them up again. When I try to create the md0 array, I am getting the following error.

/dev# mdadm --create /dev/md0 --level=1 --raid-devices=2 /dev/sda1 missing -f
mdadm: device /dev/sda1 not suitable for any style of array

It seems like Debian thinks the drive is already in an array but it's not.

# fdisk -l

Disk /dev/sda: 250.0 GB, 250000000000 bytes
255 heads, 63 sectors/track, 30394 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk identifier: 0x00000080

   Device Boot      Start         End      Blocks   Id  System
/dev/sda1   *           1       30064   241489048+  fd  Linux raid autodetect
/dev/sda2           30065       30394     2650725    5  Extended
/dev/sda5           30065       30394     2650693+  fd  Linux raid autodetect

# cat /proc/mdstat 
Personalities : [raid1] 
unused devices: <none>