As of now it is back up. If you take a look at the GDAX or Coinbase charts over the past 1-2 hours on a short timescale though (i.e. 1 || 5 minute candles on GDAX, or Past hour on coinbase app), you'll notice after the big dump, there was a large flat period where no trades were occuring, even though the site and app appeared to be up for a lot of people.