This is why companies don't announce layoffs before they know who will be impacted, as frustrating as it can be. My morale would be in the gutter too if I had to spend a month wondering whether I'm the unlucky 1 in 10.
When I was finally laid off, there was no notice at all. Ripping off the band-aid was better (though it still sucked).
It ratchets up both after the silent layoffs, and before the announced ones; after the silent refresher reductions, and the announced MCI-like initiatives.
It's nice to think morale is only bottoming out for a month, but in actuality it is spiraling catastrophically.