On Linux, the system load average values are comprised of processes in one of three different states. In general, one could say that the load average is the amount of processes waiting for CPU time or consuming CPU time. The three values in the load average overview are the load average over the past minute, the last 5 minutes and the last 15 minutes.
The three different states of processes counted towards the load average are: (1) processes running on the CPU, (2) processes waiting for CPU time and (3) processes in uninterruptable sleep. The last category, while not generating CPU load, can increase the system load average significantly.
For example, a dozen processes waiting for reads from a disk that is very busy or unavailable will generate a load average of 12 as processes in uninterruptable sleep, but your CPU can be perfectly idle in the meantime.
So, yes, load average can easily go up to double digits. How bad that is is rather dependent on your hardware. If you have 16 cores, having 16 processes waiting for CPU time is not so bad. On a single core machine, having 3 processes waiting for CPU time can be very bad.