Firstly, no it's not normal.
I concur that the likelihood is its low on PAS fluid.
Check and eliminate the PAS. If it continues, it could be the alternator belt squealing (with the engine running, give the belt/pulley a mega blast of WD40 and try to avoid the hand in the engine problem; it hurts).
You might need to squirt the belt a couple of times over a few days. If that doesn't cure it, it could be the water pump, but unlikely.