
602 N.W.2d 630 (1999)
237 Mich. App. 253
In the Matter of Zachary MARTIN, a Minor.
Walter J. Trudeau and Margerett F. Trudeau, Petitioners-Appellants,
v.
Patrick Martin and Sherry Andrews, Respondents-Appellees.
In the Matter of Shaun Martin, a Minor.
Walter J. Trudeau and Margerett F. Trudeau, Petitioners-Appellants,
v.
Patrick Martin and Sherry Andrews, Respondents-Appellees.
Docket Nos. 214400, 214824.
Court of Appeals of Michigan.
Submitted April 8, 1999, at Lansing.
Decided August 20, 1999, at 9:20 a.m.
Released for Publication December 1, 1999.
Robert W. Bennett, Purdenville, for Walter J. and Margerett Trudeau.
H. Keith DuBois, Grayling, for Sherry Andrews.
Before WILDER, P.J., and MARK J. CAVANAGH and ZAHRA, JJ.
WILDER, P.J.
Petitioners Walter J. and Margerett F. Trudeau appeal as of right the dismissal of their guardianship petitions by the Roscommon County Probate Court for lack of jurisdiction. The probate court concluded that it was divested of jurisdiction to consider the guardianship petitions filed under *631 M.C.L. § 700.424; MSA 27.5424 because the children's father Patrick Martin (hereafter Martin) had executed a power of attorney delegating parental authority to his sister Sherry Andrews (hereafter Andrews). We reverse.
Initially, we note that, at the time of oral arguments in this Court, the power of attorney granting Andrews parental authority over the minor children had expired, both by statutory dictate and because Andrews, with Martin's consent, had already voluntarily relinquished the minor children to petitioners. Thereafter, petitioners filed renewed petitions for guardianship that were uncontested by respondents and granted by the probate court. Thus, the issue before us is technically moot. We address it, nonetheless, because the issue is one which is likely to recur, yet also is likely to evade judicial review. In re Midland Publishing Co., Inc., 420 Mich. 148, 152, n. 2, 362 N.W.2d 580 (1984); In re Parole of Franciosi, 231 Mich.App. 607, 615, 586 N.W.2d 542 (1998).
A trial court's determination regarding the existence of subject-matter jurisdiction is a question of law that this Court reviews de novo. MCR 2.116(C)(4); Smith v. Smith, 218 Mich.App. 727, 729, 555 N.W.2d 271 (1996). Probate courts are courts of limited jurisdiction and derive their jurisdiction and power from statutory authority. In re Wirsing, 456 Mich. 467, 472, 573 N.W.2d 51 (1998); D'Allessandro v. Ely, 173 Mich.App. 788, 794, 434 N.W.2d 662 (1988). Probate courts have exclusive jurisdiction over guardianship proceedings. MCL 700.21(c); MSA 27.5021(c).

MCL 700.424; MSA 27.5424 provides:
(1) A person interested in the welfare of a minor, or a minor if 14 years of age or older, may petition for the appointment of a guardian of the minor. The court may order the department of social services or an employee or agent of the court to conduct an investigation of the proposed guardianship and file a written report of the investigation.
(2) The court may appoint a guardian for an unmarried minor if any of the following circumstances exist:
(a) The parental rights of both parents or of the surviving parent have been terminated or suspended by prior court order, by judgment of divorce or separate maintenance, by death, by judicial determination of mental incompetency, by disappearance, or by confinement in a place of detention.
(b) The parent or parents have permitted the minor to reside with another person and have not provided the other person with legal authority for the care and maintenance of the minor.
In the instant case, the probate court obtained jurisdiction over the guardianship proceeding when the petitioners, as persons interested in the welfare of the minor children, filed guardianship petitions pursuant to M.C.L. § 700.424; MSA 27.5424. At the time the petitions were filed, the minor children's mother was deceased and their father was incarcerated. MCL 700.424(2)(a); MSA 27.5424(2)(a). Moreover, Martin had permitted the children to reside with petitioners following their mother's death and before executing the power of attorney to Andrews without providing legal authority for the care and maintenance of the children upon his incarceration. MCL 700.424(2)(b); MSA 27.5424(2)(b). It is clear from the plain and unambiguous language in the statute that the Legislature expressly intended for the probate court to assume jurisdiction over guardianship petitions under such circumstances, and we are not persuaded that Martin's execution of a power of attorney was sufficient to divest the probate court of jurisdiction over otherwise valid guardianship petitions.
Indeed, this Court reached a similar conclusion in In re Webster, 170 Mich.App. 100, 105, 427 N.W.2d 596 (1988), where this Court rejected the respondent mother's argument that the probate court never *632 acquired jurisdiction over the minor child because the respondent executed a power of attorney granting parental authority of the child to a relative. This Court found that the Department of Social Services had submitted sufficient evidence in support of its neglect petition to permit the probate court to assume jurisdiction over the minor child under M.C.L. § 712A.2(b); MSA 27.3178(598.2)(b), and that the respondent's execution of a power of attorney "was ineffective to thwart this jurisdiction." Webster, supra at 106, 427 N.W.2d 596.
We note that by executing a power of attorney, thereby delegating his parental rights to Andrews, Martin in no way created a guardianship on behalf of Andrews. See OAG 1979-1980, No. 5782, p. 1002 (September 17, 1980). A power of attorney is, by statute, revocable at will and only effective for six months. MCL 700.405; MSA 27.5405. When the power of attorney expires, the legal authority to care for the children terminates. As such, the person with custody of the child no longer has legal power, authority, or obligation with regard to the welfare of the child. In contrast, an appointed guardian of a minor "has the powers and responsibilities of a parent" and must "facilitate the ward's education and social or other activities, and shall authorize medical or other professional care, treatment, or advice." MCL 700.431(1)(c); MSA 27.5431(1)(c). In light of the nature of the charges pending against Martin when this case originated,[1] the power of attorney granting parental authority to Andrews did not address the long-term needs of the children and, therefore, a guardianship proceeding was appropriate to ensure their well-being.
Finally, we find respondent's and the probate court's reliance on the Supreme Court's holding and rationale in In re Taurus F, 415 Mich. 512, 330 N.W.2d 33 (1982), misplaced. Taurus F does not address whether execution of a power of attorney prevents the probate court from assuming jurisdiction over guardianship proceedings pursuant to a valid petition for guardianship rights. Rather, Taurus F involved the more narrow question whether the probate court had jurisdiction under the Juvenile Code to consider a petition filed by the Department of Social Services to terminate parental rights, where the child had already been entrusted to a relative who provided a suitable home for foster care, as required by M.C.L. § 712A.2(b); MSA 27.3178(598.2)(b). Taurus F, supra at 542-543, 330 N.W.2d 33. Conversely, the instant case is not a situation in which an incarcerated parent attempts to give permanent custody of the minor children to a relative and the probate court is asked to determine whether the relative can provide proper care and a suitable home. Instead, respondent Martin attempted to temporarily transfer his parental authority to his sister pursuant to a power of attorney, without any apparent regard in planning for the long-term needs of the children. Thus, the facts and circumstances here are readily distinguishable from those presented in Taurus F, supra.[2] See also In the Matter of Pasco, 150 Mich.App. 816, 822-823, 389 N.W.2d 188 (1986).
Therefore, because we conclude that the execution of a power of attorney does not divest the probate court of jurisdiction over guardianship proceedings, In re Webster, supra, we reverse the probate court's order dismissing this action for lack of jurisdiction. However, under the unique circumstances of this case, remand for a *633 hearing regarding the petitioner's guardianship petitions is unnecessary.
Reversed.
NOTES
[1]  Martin was charged with open murder in the death of his wife, the mother of the minor children. During the pendency of this appeal, Martin was convicted of second-degree murder and was sentenced to life in prison.
[2]  We note that the holding of In re Taurus F is the product of an equally divided Supreme Court and, without a majority opinion, it is of diminished precedential value. Drielick v. Drielick, 151 Mich.App. 665, 675, 391 N.W.2d 435 (1986).
