Disk space warnings on /root

I am getting warnings that my /root directory is running out of space but when I check it, there seems to be plenty of space:

[root@Spock Scott]# df -h
Filesystem Size Used Avail Use% Mounted on
/dev/mapper/rhel-root 50G 13G 38G 26% /
devtmpfs 252G 0 252G 0% /dev
tmpfs 252G 152K 252G 1% /dev/shm
tmpfs 252G 18M 252G 1% /run
tmpfs 252G 0 252G 0% /sys/fs/cgroup
/dev/sda1 494M 202M 293M 41% /boot
/dev/sdb 28T 22T 6.2T 78% /run/media/Scott/30TB_XFS
/dev/md127p1 2.2T 1.9T 381G 84% /run/media/Scott/FIORd0_XFS
/dev/mapper/rhel-home 318G 6.3G 312G 2% /home
//kirk/kirk_c 931G 908G 24G 98% /run/media/Scott/Kirk_c
//kirk/kirk_d 1.9T 1.4T 439G 77% /run/media/Scott/Kirk_d
tmpfs 51G 28K 51G 1% /run/user/1000

I read some instructions on resizing the root directory but it seems there is already plenty of space, so I haven't tried it.

Would appreciate any advice, as I am now getting a similar warning from another system, same issue.

Thanks!