If you check https://blockchain.info/pools Ghash.io is back down to 39% of blocks created, which is still big, but not as scary.
A good explanation is due to the random variation in the who the block is a awarded to.
A good explanation is due to the random variation in the who the block is a awarded to.
In the past 24 hours, they are still at 41%.
Although I agree there's bound to be a bit of random fluctuation.