Below is an explanation of "aileron snatch" taken from Flight Standards
Information Bulletin for Air Transportation (FSAT) # 97-03 - In-flight Icing
Operations and Training Recommendations.

Ted Stanley


How can ice affect roll attitude?
   Ice can contribute to partial or total wing stall followed by roll,
aileron snatch, or reduced aileron effectiveness.

Aileron "snatch" is a descriptive term that results from an imbalance in the
sum of the product of aerodynamic forces at an AOA that may be less than
wing stall, that tends to deflect the aileron away from the neutral
position. On unpowered controls, it is felt as a change in control wheel
force. Instead of requiring force to deflect the aileron, it requires force
to return the aileron to the neutral position. All else equal, smaller
ailerons would have smaller snatch forces. Aileron instability sensed as an
oscillation, vibration or buffet in the control wheel is another tactile cue
that the flow field over the ailerons is disturbed.