An ABS question

The other day we took a drive in our '99 Tahoe in the snow and ice. As I hit the brakes I heard a terrible noise coming from under the hood and the brake pedal vibrated harshly. The Tahoe came to a stop without any wheel lock but the noise and vibration was a bit unnerving to both myself and my wife. I think this is the first time I had noticed the ABS system do its job. Is this the normal sound of the ABS system doing its job?

Sounds like it.