Curling skips sweeping signals

The skip calls the line, and inquires about where the sweepers think the rock will end up.

1. Sweep signal

The hand is held palm up, gesturing in a beckoning motion.

2. No sweeping signal

The hand is help palm up, gesturing  a stationary traffic stop

Sweeping rocks after the curl begins does two things:

1. It reduces the amount of additional curl.

2. It keeps the rock moving on its current path.