Push The Bar Back Not Up To The Hips
In the snatch, we need to use the lats to keep the bar close and moving into the hips as we extend.
A common mistake is to overdo this and actually lift the bar up instead of just pushing it back toward the body.
This moves the bar too far back and against the hips early, which means the hips drive it straight forward as you extend the body.
On top of this, it temporarily prevents the extension of the body from actually lifting the bar—the bar slows down and may even come to a complete stop before accelerating again.
By pushing the bar back properly, it comes into the hips as the hips move above the feet and begin moving up, allowing the leg and hip extension to move the bar up instead of the hips pushing it forward.
Think of using the lats to push the bar back while allowing it to hang from the shoulders so it simply remains close at its present height. Remember that this push back is less of a movement than the prevention of movement— simply keep the bar as close to the legs as possible as you execute the pull, rather than allowing it to move away.