The difference is when the anchor lets go. A skipped anchor forms briefly and then leaves the water before the delivery cast, moving away from the target. A blown anchor stays until the delivery cast begins and then releases prematurely during it.

Both are premature releases, which is why the names get mixed up. The test is the clock and the direction: did the anchor go early and away from the target, or did it hold until the forward stroke and then let go?

That timing is central to the distinction, so a vague answer fails. “The anchor slipped” does not identify either fault. Name when it left, and for the skipped anchor add that it went away from the target.

On the water, the two feel different in the hand. A skipped anchor is gone while you are still setting up; a blown anchor is there when you start forward and gone before the delivery can use it. Watch the anchor, not the loop, and you will catch which one you have.

Source

From the FFI Fly Casting Definitions (August 2025); terms follow the FFI Fly Casting Definitions (Skipped Anchor, Blown Anchor).