House power went off. Now Red Alert hard drive failure of one of four drives. Advice?

DDR3A (Gen 3)

About the time the electricity in my house went out, the Drobo shut off, even tho it was connected to my UPS battery backup. Everything else stayed on for me to shut it down in time.

When I powered the Drobo back on, I got this email warning:

Red Alert. Drobo detected a hard drive failure. Replace the hard drive indicated by the blinking red light.

The RAID is rebuilding. Does it sound like the red alert drive is really fried?