Colo. Rev. Stat. § 13-16-102
If an action described in section 13-16-101(2) is commenced by a nonresident of this state without filing an instrument in writing, or if at any time after the commencement of any suit by a resident of this state he or she shall become nonresident, and the court is satisfied that the nonresident plaintiff is unable to pay the costs of suit, the court may, on motion of the defendant or any officer of the court, order the nonresident plaintiff, on or before the day in such order named, to give an instrument in writing for the payment of costs in the suit. To ensure that access to the courts is not unreasonably denied, a court shall not require an instrument in writing for the payment of costs of suit in excess of five thousand dollars. If the nonresident plaintiff neglects or refuses, on or before the day in such rule named, to file such instrument, the court, on motion, shall dismiss the suit.
C.R.S. § 13-16-102