A balloon includes a cut-down device, a payload, and an envelope. A control system could be configured to determine a position of the balloon with respect to a predetermined zone. The cut-down device could be operable to cause at least the payload to land in response to determining that the position of the balloon is within the predetermined zone. The predetermined zone includes an exclusion zone and a shadow zone. The shadow zone could include locations from which the balloon would be likely to drift into the exclusion zone based on, e.g., historic weather patterns or expected environmental conditions. Boundaries of the shadow zone could be determined based on, for example, a probability of the balloon entering the exclusion zone.