¶1delivered the Opinion of the Court.
¶2The People of the State of Colorado appeal the trial court’s ruling that section 42-2-123.6, 17 C.R.S. (1993), requiring defendants convicted of certain drug offenses to surrender their drivers licenses to the court for forwarding to the Colorado Department of Revenue, violates the principle of separation of powers found in Article III of the Colorado Constitution.
¶3I
¶4On May 11, 1992, an anonymous caller (the informant) contacted Officer Thomas A. Leh-mann (Officer Lehmann) of the Colorado Springs Police Department to report that an individual by the name of Michael Acosta (Acosta) had been arrested one week earlier on outstanding warrants from New Mexico. The informant specified that the warrants had been for narcotics offenses. She also reported to Officer Lehmann that, according to a friend of hers, whose name she would not divulge, Acosta called his girlfriend, Lola Schafer, to request that she arrange to have *688marihuana removed from his residence because the police “were on to him.” The informant told Officer Lehmann that her friend had overheard a telephone conversation between Schafer and someone named “Donny.” Schafer was using the friend’s phone at that time. The informant stated that her friend saw Schafer dial the number “260-1716” and speak to a person she believed to be “Donny.” During that conversation, the friend heard Schafer arrange for Donny to pick up thirty-three pounds of marihuana from Acosta’s residence and store it at Donny’s residence. The informant stated that she had not previously met Donny or Schafer and did not know where Donny lived.
¶5In response to this tip, Officer Lehmann called 260-1716 and spoke to a woman who identified herself as “Mrs. Pate” and stated that she lived at 2853 Buttermilk Circle.
¶6Based upon the informant’s tip and his own efforts to corroborate that information, Officer Lehmann applied for and received a warrant to search the Pate residence at 2853 Buttermilk Circle.
¶7Soon thereafter, Pate arrived at the residence and was arrested and taken into custody. After waiving his Miranda
¶8Prior to trial, Pate filed a motion to suppress evidence seized from his residence, claiming that the search warrant was insufficient on its face and that Officer Lehmann’s affidavit in support of the search warrant failed to set forth probable cause to believe that contraband was located at Pate’s residence. Following a hearing on this issue, the trial court denied the motion, stating that “it is clear to the Court that there is sufficient *689corroboration to establish that the anonymous caller was reliable and that there is a fair probability that contraband would be found at the residence to be searched.”
¶9Pate waived his right to a trial by jury, and, after a trial to the court on March 3, 1993, he.was convicted of possession of marihuana with the intent to distribute, a class four felony. The trial court also found that although the prosecution had proved that Pate possessed marihuana with the intent to distribute, it failed to prove beyond a reasonable doubt that the net weight of the marihuana, excluding packaging materials and contaminates, was greater than eight ounces. The trial court therefore convicted Pate of possession of between one and eight ounces of marihuana, a class one misdemeanor.
¶10After a sentencing hearing on April 7, 1993, the trial court sentenced Pate to three years of probation. At that hearing, the prosecution requested that Pate be ordered to surrender his driver’s license to the trial court pursuant to section 42-2-123.6. The trial court refused, however, ruling that it was an unconstitutional violation of the separation-of-powers doctrine to compel the court to take a convicted defendant’s driver’s license for forwarding to the Department of Revenue, because it would cause a judicial officer to become a bailee acting for the benefit of the executive branch. After a hearing on the prosecution’s motion for reconsideration, the trial court adhered to its prior ruling that section 42-2-123.6 was unconstitutional.
¶11The prosecution then filed a timely notice of appeal with this court, pursuant to section 16-12-102(1), 8A C.R.S. (1986 & 1993 Supp.), and C.A.R. 4(b)(2). Pate also filed a timely notice of appeal to the court of appeals, challenging the trial court’s judgment of conviction. This court granted Pate’s motion to consolidate the two appeals.
¶12II
¶13First we will address Pate’s argument that the trial court committed reversible error in denying his motion to suppress the marihuana seized at his residence pursuant to the search warrant. Pate claims that Officer Lehmann’s affidavit in support of the search warrant did not contain sufficient information to support a finding of probable cause. We disagree.
¶14Probable cause for a search warrant exists when the affidavit in support of the warrant alleges sufficient facts to warrant a person of reasonable caution to believe that contraband or other evidence of criminal activity is located at the place to be searched. People v. Arellano, 791 P.2d 1135, 1137 (Colo.1990); People v. Quintana, 785 P.2d 934, 937 (Colo.1990). Whether an affidavit based on information provided by a confidential informant satisfies the constitutional standard of probable cause must be evaluated on the basis of the totality-of-the-circumstances test formulated by the United States Supreme Court in Illinois v. Gates, 462 U.S. 213, 103 S.Ct. 2317, 76 L.Ed.2d 527 (1983) (abandoning the two-pronged Aguilar-Spinelli test). People v. Turcotte-Schaeffer, 843 P.2d 658, 660 (Colo.1993); People v. Pannebaker, 714 P.2d 904, 907 (Colo.1986) (adopting the Gatestest in construing the Search and Seizure Clause of the Colorado Constitution). The GatesCourt emphasized that a judge or magistrate reviewing an application for a search warrant should make “a practical, common-sense decision whether, given all the circumstances set forth in the affidavit before him, including the ‘veracity’ and ‘basis of knowledge’ of persons supplying hearsay information, there is a fair probability that contraband or evidence of a crime will be found in a particular place.” 462 U.S. at 238, 103 S.Ct. at 2332.
¶15Under the totality-of-the-cireum-stances test, “an informant’s account of criminal activities need not establish the informant’s basis of knowledge, so long as the informant’s statement is sufficiently detailed to allow a judge to reasonably conclude that the informant had access to reliable information about the illegal activities reported to the police.” People v. Abeyta, 795 P.2d 1324, 1327-28 (Colo.1990). Moreover, even if an affidavit does not establish the informant’s basis of knowledge or the veracity of the reported information, police corroboration of some of the information provided by the informant may be sufficient to support a find*690ing of probable cause, even where all of the corroborated details relate to noncriminal activity. People v. Leftwich, 869 P.2d 1260, 1267-68 (Colo.1994); Turcotte-Schaeffer, 843 P.2d at 661; see also People v. Paquin, 811 P.2d 394, 397 (Colo.1991) (“A sufficiently detailed description of the informant’s observations, or an averment outlining independent corroboration of some details of the tip, may be sufficient to permit both an issuing judge and a reviewing court to conclude that the informant had access to reliable information about the illegal activities described in the affidavit.”). As we previously held in Abeyta, “because an informant is shown to be right about some things, [s]he is probably right about other facts that [s]he has alleged, including the claim that the object of the tip is engaged in criminal activity.” 795 P.2d at 1327.
¶16A magistrate’s probable cause determination is given great deference and is not reviewed de novo. Leftwich, 869 P.2d at 1266. Rather, the duty of a court reviewing the sufficiency of an affidavit on a motion to suppress is simply to ensure that the issuing judge had a “substantial basis” for concluding that probable cause existed. Gates, 462 U.S. at 238-39, 103 S.Ct. at 2332-33; Turcotte-Schaeffer, 843 P.2d at 660. In making that determination, a reviewing court must restrict itself to the four corners of the affidavit and must analyze the affidavit in a “nontechnical and common sense fashion.” Paquin, 811 P.2d at 398; see also People v. Lubben, 739 P.2d 833, 834-35 (Colo.1987). Finally, we have held that “doubts must be resolved in favor of magistrates’ determinations of probable cause in order to avoid giving police an incentive to resort to war-rantless searches in the hope of relying on consent or some other exception to the warrant requirement that might develop at the time of search.” Abeyta, 795 P.2d at 1327-28; People v. Varrieur, 771 P.2d 895, 897 (Colo.1989); see also Gates, 462 U.S. at 236, 103 S.Ct. at 2331.
¶17In this case, Pate advances several reasons why, in his view, Officer Leh-mann’s affidavit did not provide the issuing judge with a substantial basis for concluding that probable cause existed to search Pate’s home. His first claim is that the anonymous tip, by itself, failed to provide the kind of “detailed, intimate knowledge” about Pate and his activities which would indicate that the informant knew Pate personally.
¶18It is important to note at the outset that there is no requirement under the Gatestotality-of-the-circumstances test that an anonymous tip contain a highly detailed description of a suspect or the alleged criminal activity in which he or she is involved. Rather, the amount of detail provided in the tip is merely one of several factors which an issuing court should consider in determining the reliability or veracity of that information. Gates, 462 U.S. at 244, 103 S.Ct. at 2335; see also Paquin, 811 P.2d at 397. Yet, where the details provided by the informant indicate familiarity with the implicated individual or the alleged criminal activity or are facts which are difficult to obtain, the issuing judge may properly conclude that it was not unlikely that the informant had access to reliable information about the alleged illegal activities. Gates, 462 U.S. at 245, 103 S.Ct. at 2335-36; Leftwich, 869 P.2d at 1268.
¶19In this case, the details provided by the informant included: (1) the type of contra*691band involved (marihuana); (2) the precise amount of marihuana allegedly located in “Donny’s” residence (thirty-three pounds); (3) the role allegedly played by “Donny” in this drug scheme (storing the marihuana for Michael Acosta while Acosta was incarcerated); (4) “Donny’s” phone number (260-1716); (5) the name of Acosta’s girlfriend (“Lola Schafer”); and (6) the fact that Acosta recently had been arrested on outstanding New Mexico warrants for drug offenses. On the one hand, the reference to thirty-three pounds of marihuana, the information about Acosta’s arrest on New Mexico warrants, and the phone number for “Donny” are fairly specific factual details.
¶20Even if an anonymous tip, on its face, does not provide enough detailed information to establish that the informant had access to reliable information, independent police corroboration of some of those details which were provided in the tip nevertheless may support a finding of probable cause.
¶21As we noted above, the informant provided a fairly detailed account of a conspiracy to transfer a specified amount of marihuana in order to avoid detection by the police. The informant set forth the mechanics of the transaction as follows: Acosta had been arrested recently on drug charges and feared that the police “were on to him;” Acosta called his girlfriend, Lola Schafer, and asked her to arrange to have thirty-three pounds of marihuana removed from his residence; Schafer then called “Donny” and arranged for Donny to pick up the marihuana from Acosta’s residence and transport it to Donny’s residence for storage.
¶22*692Officer Lehmann corroborated the informant’s specific statements about Acosta and his recent arrest on New Mexico warrants for drug offenses. He also checked Acosta’s criminal record and discovered that Acosta had been arrested previously for conspiracy to sell marihuana and that an anonymous Crime Stoppers report indicated that he regularly sold marihuana. Officer Lehmann then called the El Paso Criminal Justice Center and confirmed that Acosta was incarcerated at that facility. Officer Lehmann also called the phone number given by the informant and determined that a Mrs. Pate lived at that residence, 2853 Buttermilk Circle. After checking the utilities listing for 2853 Buttermilk Circle, Officer Lehmann learned that a “Donald H. Pate” lived at that residence. Finally, Officer Lehmann checked the criminal history for “Donald H. Pate” and found a traffic record but no criminal arrests.
¶23Although it may have been possible for Officer Lehmann to corroborate even more of the information provided by the informant, we disagree with Pate that additional police investigation of the tip was required in order to support the issuance of a search warrant for 2853 Buttermilk Circle.
¶24Pate next claims the police also should have verified that Acosta did in fact have a girlfriend named Lola Schafer and that Schafer actually was speaking with Pate during the conversation in question. Although we agree that independent corroboration of the relationship between Acosta and Schafer would have constituted additional evidence of the informant’s reliability, it was not a prerequisite to a finding of probable cause. See Gates, 462 U.S. at 246, 103 S.Ct. at 2336. Because several other facts provided by the informant, some of which could not have been easily obtained, were proven to be accurate, the issuing judge reasonably could have inferred from the information included in the affidavit that the informant’s allegations of criminal activity were reliable. Abeyta, 795 P.2d at 1327 (“[Bjecause an informant is shown to be right about some things, [s]he is more probably right about other facts [s]he has alleged, including the claim that the object of the tip is engaged in criminal activity.”). Furthermore, any attempt by Officer Lehmann to verify the alleged conversation between Schafer and “Donny” almost certainly would have alerted the suspects that the police were investigating their activities. We disagree with Pate’s suggestion that the police were required, as a prerequisite to a finding of probable cause, to jeopardize their entire investigation in order to verify a particular factual detail provided by an informant. Such a rule would be unreasonable and would give the police a strong incentive to resort to warrantless searches. See id. at 1327-28.
¶25Pate’s final claim is that anonymous informants are “inherently unreliable” and that, in cases involving anonymous tips, this court should require the police to do “extensive” corroboration before probable cause will be *693found. As the Supreme Court noted in Gates, however, anonymous tips, “particularly when supplemented by independent police investigation, frequently contribute to the solution of otherwise ‘perfect crimes.’ ” 462 U.S. at 237-38, 103 S.Ct. at 2332. Therefore, “[w]hile a conscientious assessment of the basis for crediting such tips is required by the Fourth Amendment, a standard that leaves virtually no place for anonymous citizen tips is not.” Id. at 235, 103 S.Ct. at 2330-31. In this case, we have considered the tip on its face and in light of the independent police corroboration described in the affidavit. We agree with the trial court that, under the totality of the circumstances, a substantial basis exists to support the issuing judge’s determination that probable cause existed to search Pate’s residence. See Abeyta, 795 P.2d at 1327-28 (doubts must be resolved in favor of magistrates’ determinations of probable cause). Accordingly, we affirm the trial court’s judgment of conviction against Pate.
¶26Ill
¶27We will now address the People’s argument that the trial court erred in finding that section 42-2-123.6 violates Article III of the Colorado Constitution. The People claim that the trial court’s ruling was premised on a misunderstanding of the separation-of-powers doctrine. We agree.
¶28Article III of the Colorado Constitution provides:
The powers of the government of this state are divided into three distinct departments- — the legislative, executive and judicial; and no person or collection of persons charged with the exercise of powers properly belonging to one of these departments shall exercise any power properly belonging to either of the others, except as in this constitution expressly directed or permitted.
¶29In construing Article III, we have held that the separation-of-powers doctrine “imposes on the judiciary both a proscription against interfering with the executive or legislative branches, and a duty to perform its constitutional and statutory obligations with complete independence.” People v. Zapotocky, 869 P.2d 1234, 1244 (Colo.1994); Pena v. District Court, 681 P.2d 953, 956 (Colo.1984). The mere fact of cooperation between two branches of government, however, does not establish a separation-of-powers violation. Smith v. Miller, 153 Colo. 35, 40-41, 384 P.2d 738, 741 (1963) (noting that “the three departments of government are coordinate and shall co-operate with and complement” each other); see also Nixon v. Administrator of General Services, 433 U.S. 425, 443, 97 S.Ct. 2777, 2790, 53 L.Ed.2d 867 (1977) (rejecting argument that U.S. Constitution contemplates a “complete division of authority between the three branches”).
¶30The question before us in this case is thus whether section 42-2-123.6’s requirement that the trial court forward a defendant’s driver’s license to the Department of Revenue amounts to an unconstitutional interference with the executive branch’s statutory duty to enforce the laws governing the revocation of drivers’ licenses.
¶31Section 42-2-123.6 provides in pertinent part as follows:
Immediately upon a plea of guilty or nolo contendere or a verdict of guilty by the court or a jury, to an offense for which revocation of a license or permit is mandatory pursuant to section 42-2-122(l)((), the court shall require the offender to immediately surrender his driver’s ... license or instruction permit to the court. The court shall forward to the [Department of Revenue] a notice of plea or verdict ..., together with the offender’s li*694cense or permit, not later than ten days after the surrender of the license or permit.
¶32§ 42-2-123.6, 17 C.R.S. (1993). Section 42-2-122(l)(i) requires the Department of Revenue to revoke the license of a driver upon receiving notice that the driver has “[b]een convicted of any felony offense provided for in [sections 18-18-404 to -406, 8B C.R.S. (1993 Supp.) ].” Sections 18-18-404 to -406 define the offenses of unlawful use, sale and possession of controlled substances.
¶33The Department of Revenue is assigned by statute the duty to enforce the provisions in section 42-2-122 governing the revocation of drivers’ licenses. However, the General Assembly expressly reserved to the judiciary the specific task of seizing and forwarding to the Department of Revenue the drivers’ licenses of those defendants convicted of specified drug offenses. § 42-2-123.6. It cannot plausibly be argued that in complying with section 42-2-123.6 a trial court would violate the doctrine of separation of powers.
¶34It is axiomatic that the judiciary has the exclusive power to impose sentences which fall within the limits determined by the General Assembly. People v. Montgomery, 669 P.2d 1387, 1390 (Colo.1983); People v. Schwartz, 823 P.2d 1386, 1386-87 (Colo.App.1991). In this case, the General Assembly specifically included the power to seize the driver’s license from an offender and to forward it to the Department of Revenue within the range of sanctions available to trial courts when sentencing persons convicted of certain drug offenses. See Zinn, 843 P.2d at 1363-56 (describing the license revocation and forwarding provisions as “sanctions designed to prevent criminal conduct and to punish persons who engage in criminal conduct”). Thus, a trial court’s decision to seize and forward an offender’s license to the Department of Revenue pursuant to sections 42-2-123.6 and 42 — 2—122(1)(£), is clearly encompassed within its sentencing authority.
¶35Furthermore, the fact that a court, in exercising such authority, is “cooperating” with the executive branch in an effort to enforce the license-revocation statute does not mean that the judiciary is thereby “interfering” with those duties statutorily committed to the executive branch. Smith, 153 Colo. at 40-41, 384 P.2d at 741. Rather, the license-forwarding requirement in section 42-2-123.6 is precisely the type of practical interbranch cooperation which is implicit in the notion of a government of separate but “coordinate” powers. See id.To hold otherwise would severely limit the fundamental purpose underlying Article III, that is, to provide for “the orderly distribution of power among the three branches of state government.” Montgomery, 669 P.2d at 1389 (emphasis added).
¶36Accordingly, we reverse the tidal court’s ruling that section 42-2-123.6 violates the separation-of-powers doctrine under Article III of the Colorado Constitution and remand the case to that court for further proceedings consistent with this opinion.
¶37. Because the decision below involved a determination of the constitutionality of a statute, this court has jurisdiction to resolve the appeal. See § 13-4-102(l)(b), 6A C.R.S. (1987).
¶38. See § 13-4-109, 6A C.R.S. (1987).
¶39. The factual details regarding Officer Leh-mann’s efforts to corroborate the informant's tip are set forth in his affidavit in support of the search warrant.
¶40. Acosta's record also indicated that he had been arrested previously for conspiracy to sell marihuana, felony larceny and first degree criminal trespass, and that Crime Stoppers had received an anonymous report that an individual had been purchasing marihuana from Acosta on a regular basis.
¶41. Approximately six hours elapsed between the time Officer Lehmann received the anonymous tip and when he applied for the search warrant. Judge Sletta of the El Paso County Court issued the search warrant on the evening of May 11, 1992.
¶42. The question of whether Mrs. Pate's consent was validly obtained prior to the presentation of the search warrant was not addressed by the trial court. Although Pate raised this issue initially in his motion to suppress, the parties did not argue the consent issue once the trial court concluded that the search warrant was validly issued.
¶43. Miranda v. Arizona, 384 U.S. 436, 86 S.Ct. 1602, 16 L.Ed.2d 694 (1966).
¶44. § 18-18-106(4)(b), 8B C.R.S, (1986).
¶45. § 18-18-106(8)(b), 8B C.R.S. (1986).
¶46. Pate claims, for example, that the informant’s information was presumptively unreliable because it constituted "double hearsay” and was not based on the informant’s direct observations. However, ”[w]hen a magistrate receives an affidavit which contains hearsay upon hearsay, he need not categorically reject this double hearsay information. Rather, he is called upon to evaluate this information as well as other information in the affidavit in order to determine whether it can be reasonably inferred 'that the informant had gained his information in a reliable way.’ ” United States v. Smith, 462 F.2d 456, 459 (8th Cir.1972); accord United States v. Townsley, 843 F.2d 1070, 1078 (8th Cir.1988); United States v. McCoy, 478 F.2d 176, 179 (10th Cir.1973). Under the Gates test, independent corroboration of details provided by an informant is one way to establish the reliability of double hearsay information. See State v. Niehaus, 452 N.W.2d 184, 190-91 (Iowa 1990).
¶47. The trial court recognized this point in its order denying Pate’s motion to suppress:
The information given by the caller about the arrest of Acosta, about the nature of narcotics, and about his girlfriend [were] very specifically identified type[s] of information; [they weren't] general types of statements.
¶48. The People argue that because "Donny’s” phone number was unlisted, it should also be considered information that was difficult to obtain and thus more reliable. The problem with this argument is that Officer Lehmann's affidavit did not specify that the number "260-1716” was unlisted. That fact is therefore irrelevant to our determination of whether probable cause existed to support the search warrant. Paquin, 811 P.2d at 398.
¶49.Other “indicia of reliability” which have been found to support a finding of probable cause include, for example, a statement by the affiant that the informant previously had given reliable information to the police, and the fact that the tip contained a declaration against the informant's penal interest. See Gates, 462 U.S. at 227, 103 S.Ct. at 2326; Leftwich, 869 P.2d at 1266.
¶50. This case is thus distinguishable in an important respect from Leftwich. Here, there is no doubt that the information reported to Officer Lehmann established a "nexus between the alleged illegal activity and [the defendant’s] home.” Leftwich, 869 P.2d at 1268. The informant’s statement that the marihuana would be stored in "Donny’s” residence, combined with the fact that "Donny’s” phone number was traced by Officer Lehmann to Pate’s residence, adequately connects the marihuana and the location ultimately searched.
¶51. It is equally reasonable to assume that surveillance of Pate's residence would have added little to the probable cause calculus in light of the allegation by the informant that Pate was merely storing the marihuana and not selling or otherwise distributing it.
¶52. The trial court based its finding of a violation of separation of powers on the fact that, in its view, section 42-2-123.6 transformed the court into a "bailee” acting for the sole benefit of the executive branch. It apparently concluded that the act of forwarding a driver’s license to the Department of Revenue for revocation purposes did not constitute the type of interbranch "cooperation” permissible under Article III.